Diff of the two buildlogs:

--
--- b1/build.log	2025-02-24 20:41:58.488560498 +0000
+++ b2/build.log	2025-02-24 20:43:35.484207586 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Sun Mar 29 15:04:12 -12 2026
-I: pbuilder-time-stamp: 1774839852
+I: Current time: Tue Feb 25 10:42:01 +14 2025
+I: pbuilder-time-stamp: 1740429721
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/trixie-reproducible-base.tgz]
 I: copying local configuration
@@ -24,52 +24,84 @@
 dpkg-source: info: applying privacy.patch
 I: using fakeroot in build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/411410/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/D01_modify_environment starting
+debug: Running on ionos1-amd64.
+I: Changing host+domainname to test build reproducibility
+I: Adding a custom variable just for the fun of it...
+I: Changing /bin/sh to bash
+'/bin/sh' -> '/bin/bash'
+lrwxrwxrwx 1 root root 9 Feb 24 20:42 /bin/sh -> /bin/bash
+I: Setting pbuilder2's login shell to /bin/bash
+I: Setting pbuilder2's GECOS to second user,second room,second work-phone,second home-phone,second other
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/D02_print_environment starting
 I: set
-  BUILDDIR='/build/reproducible-path'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
-  BUILD_ARCH='amd64'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=42 '
-  DISTRIBUTION='trixie'
-  HOME='/root'
-  HOST_ARCH='amd64'
+  BASH=/bin/sh
+  BASHOPTS=checkwinsize:cmdhist:complete_fullquote:extquote:force_fignore:globasciiranges:globskipdots:hostcomplete:interactive_comments:patsub_replacement:progcomp:promptvars:sourcepath
+  BASH_ALIASES=()
+  BASH_ARGC=()
+  BASH_ARGV=()
+  BASH_CMDS=()
+  BASH_LINENO=([0]="12" [1]="0")
+  BASH_LOADABLES_PATH=/usr/local/lib/bash:/usr/lib/bash:/opt/local/lib/bash:/usr/pkg/lib/bash:/opt/pkg/lib/bash:.
+  BASH_SOURCE=([0]="/tmp/hooks/D02_print_environment" [1]="/tmp/hooks/D02_print_environment")
+  BASH_VERSINFO=([0]="5" [1]="2" [2]="37" [3]="1" [4]="release" [5]="x86_64-pc-linux-gnu")
+  BASH_VERSION='5.2.37(1)-release'
+  BUILDDIR=/build/reproducible-path
+  BUILDUSERGECOS='second user,second room,second work-phone,second home-phone,second other'
+  BUILDUSERNAME=pbuilder2
+  BUILD_ARCH=amd64
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=20 '
+  DIRSTACK=()
+  DISTRIBUTION=trixie
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=x86_64
+  HOST_ARCH=amd64
   IFS=' 	
   '
-  INVOCATION_ID='4c7ae482fc1f4433bc55691ae446f8ff'
-  LANG='C'
-  LANGUAGE='en_US:en'
-  LC_ALL='C'
-  MAIL='/var/mail/root'
-  OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
-  PBCURRENTCOMMANDLINEOPERATION='build'
-  PBUILDER_OPERATION='build'
-  PBUILDER_PKGDATADIR='/usr/share/pbuilder'
-  PBUILDER_PKGLIBDIR='/usr/lib/pbuilder'
-  PBUILDER_SYSCONFDIR='/etc'
-  PPID='411410'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=8b49a12555e54e8bbc1b6c060af04226
+  LANG=C
+  LANGUAGE=et_EE:et
+  LC_ALL=C
+  MACHTYPE=x86_64-pc-linux-gnu
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnu
+  PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path
+  PBCURRENTCOMMANDLINEOPERATION=build
+  PBUILDER_OPERATION=build
+  PBUILDER_PKGDATADIR=/usr/share/pbuilder
+  PBUILDER_PKGLIBDIR=/usr/lib/pbuilder
+  PBUILDER_SYSCONFDIR=/etc
+  PIPESTATUS=([0]="0")
+  POSIXLY_CORRECT=y
+  PPID=720942
   PS4='+ '
-  PWD='/'
-  SHELL='/bin/bash'
-  SHLVL='2'
-  SUDO_COMMAND='/usr/bin/timeout -k 18.1h 18h /usr/bin/ionice -c 3 /usr/bin/nice /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.U5GuyVto/pbuilderrc_iT2e --distribution trixie --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.U5GuyVto/b1 --logfile b1/build.log pgn-extract_19.04-1.dsc'
-  SUDO_GID='110'
-  SUDO_UID='105'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://213.165.73.152:3128'
+  PWD=/
+  SHELL=/bin/bash
+  SHELLOPTS=braceexpand:errexit:hashall:interactive-comments:posix
+  SHLVL=3
+  SUDO_COMMAND='/usr/bin/timeout -k 24.1h 24h /usr/bin/ionice -c 3 /usr/bin/nice -n 11 /usr/bin/unshare --uts -- /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.U5GuyVto/pbuilderrc_Jcwx --distribution trixie --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/trixie-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.U5GuyVto/b2 --logfile b2/build.log pgn-extract_19.04-1.dsc'
+  SUDO_GID=110
+  SUDO_UID=105
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://46.16.76.132:3128
 I: uname -a
-  Linux ionos5-amd64 6.12.9+bpo-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.9-1~bpo12+1 (2025-01-19) x86_64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-31-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.128-1 (2025-02-07) x86_64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 Nov 22  2024 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/411410/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -135,7 +167,7 @@
 Get: 28 http://deb.debian.org/debian trixie/main amd64 intltool-debian all 0.35.0+20060710.6 [22.9 kB]
 Get: 29 http://deb.debian.org/debian trixie/main amd64 po-debconf all 1.0.21+nmu1 [248 kB]
 Get: 30 http://deb.debian.org/debian trixie/main amd64 debhelper all 13.24.1 [920 kB]
-Fetched 20.6 MB in 3s (6486 kB/s)
+Fetched 20.6 MB in 3s (7881 kB/s)
 Preconfiguring packages ...
 Selecting previously unselected package sensible-utils.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 19802 files and directories currently installed.)
@@ -275,7 +307,11 @@
 fakeroot is already the newest version (1.37-1).
 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
 I: Building the package
-I: Running cd /build/reproducible-path/pgn-extract-19.04/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-genchanges -S  > ../pgn-extract_19.04-1_source.changes
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for trixie
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/pgn-extract-19.04/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-genchanges -S  > ../pgn-extract_19.04-1_source.changes
 dpkg-buildpackage: info: source package pgn-extract
 dpkg-buildpackage: info: source version 19.04-1
 dpkg-buildpackage: info: source distribution unstable
@@ -285,7 +321,7 @@
  debian/rules clean
 dh clean
    dh_auto_clean
-	make -j42 clean
+	make -j20 clean
 make[1]: Entering directory '/build/reproducible-path/pgn-extract-19.04'
 rm -f core pgn-extract *.o
 make[1]: Leaving directory '/build/reproducible-path/pgn-extract-19.04'
@@ -296,7 +332,7 @@
    dh_autoreconf
    dh_auto_configure
    dh_auto_build
-	make -j42 "INSTALL=install --strip-program=true"
+	make -j20 "INSTALL=install --strip-program=true"
 make[1]: Entering directory '/build/reproducible-path/pgn-extract-19.04'
 gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 grammar.c
 gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 lex.c
@@ -315,11 +351,6 @@
 gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 mymalloc.c
 gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 fenmatcher.c
 gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 taglines.c
-gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 zobrist.c
-argsfile.c: In function 'usage_and_exit':
-argsfile.c:252:30: warning: macro "__DATE__" might prevent reproducible builds [-Wdate-time]
-  252 |             CURRENT_VERSION, __DATE__);
-      |                              ^~~~~~~~
 output.c: In function 'print_items_following_move':
 output.c:959:56: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 3 has type 'uint64_t' {aka 'long unsigned int'} [-Wformat=]
   959 |             fprintf(outputfile, ", \"HashCode\" : \"%llx\"",
@@ -338,6 +369,11 @@
       |                                   |               uint64_t {aka long unsigned int}
       |                                   long long unsigned int
       |                                %lx
+gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/pgn-extract-19.04=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -c -pedantic -Wall -Wshadow -Wformat -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wsign-compare -Wimplicit-function-declaration -g -I/usr/local/lib/ansi-include -std=c99 -Wdate-time -D_FORTIFY_SOURCE=2 -O3 zobrist.c
+argsfile.c: In function 'usage_and_exit':
+argsfile.c:252:30: warning: macro "__DATE__" might prevent reproducible builds [-Wdate-time]
+  252 |             CURRENT_VERSION, __DATE__);
+      |                              ^~~~~~~~
 map.c: In function 'generate_pawn_moves':
 map.c:2147:27: warning: array subscript -1 is below array bounds of 'const Piece[12]' [-Warray-bounds=]
  2147 |     if (board->board[to_r][to_c] == OFF) {
@@ -369,8 +405,8 @@
    dh_gencontrol
    dh_md5sums
    dh_builddeb
-dpkg-deb: building package 'pgn-extract' in '../pgn-extract_19.04-1_amd64.deb'.
 dpkg-deb: building package 'pgn-extract-dbgsym' in '../pgn-extract-dbgsym_19.04-1_amd64.deb'.
+dpkg-deb: building package 'pgn-extract' in '../pgn-extract_19.04-1_amd64.deb'.
  dpkg-genbuildinfo --build=binary -O../pgn-extract_19.04-1_amd64.buildinfo
  dpkg-genchanges --build=binary -O../pgn-extract_19.04-1_amd64.changes
 dpkg-genchanges: info: binary-only upload (no source code included)
@@ -378,12 +414,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: including full source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/720942/tmp/hooks/B01_cleanup finished
 I: unmounting dev/ptmx filesystem
 I: unmounting dev/pts filesystem
 I: unmounting dev/shm filesystem
 I: unmounting proc filesystem
 I: unmounting sys filesystem
 I: cleaning the build env 
-I: removing directory /srv/workspace/pbuilder/411410 and its subdirectories
-I: Current time: Sun Mar 29 15:04:57 -12 2026
-I: pbuilder-time-stamp: 1774839897
+I: removing directory /srv/workspace/pbuilder/720942 and its subdirectories
+I: Current time: Tue Feb 25 10:43:34 +14 2025
+I: pbuilder-time-stamp: 1740429814