Diff of the two buildlogs:

--
--- b1/build.log	2025-01-26 11:02:47.355634460 +0000
+++ b2/build.log	2025-01-26 11:03:28.773766272 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Sat Jan 25 22:57:39 -12 2025
-I: pbuilder-time-stamp: 1737889059
+I: Current time: Sun Mar  1 07:25:47 +14 2026
+I: pbuilder-time-stamp: 1772299547
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/trixie-reproducible-base.tgz]
 I: copying local configuration
@@ -26,52 +26,84 @@
 dpkg-source: info: applying fix-thinko.patch
 I: using fakeroot in build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/2139040/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/4081507/tmp/hooks/D01_modify_environment starting
+debug: Running on ionos15-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 28 17:25 /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/4081507/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/4081507/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=20 '
-  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=42 '
+  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='e9dd793bbaa344c585db0c250027db7d'
-  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='2139040'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=0f5735a0df5a42dd94bec950ec3a6b3b
+  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=4081507
   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.HDlgyptS/pbuilderrc_aL5y --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.HDlgyptS/b1 --logfile b1/build.log ws-butler_0.7-1.dsc'
-  SUDO_GID='111'
-  SUDO_UID='106'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://46.16.76.132:3128'
+  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.HDlgyptS/pbuilderrc_YonR --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.HDlgyptS/b2 --logfile b2/build.log ws-butler_0.7-1.dsc'
+  SUDO_GID=111
+  SUDO_UID=106
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://213.165.73.152:3128
 I: uname -a
-  Linux ionos11-amd64 6.1.0-30-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.124-1 (2025-01-12) x86_64 GNU/Linux
+  Linux i-capture-the-hostname 6.12.9+bpo-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.9-1~bpo12+1 (2025-01-19) x86_64 GNU/Linux
 I: ls -l /bin
-  lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/2139040/tmp/hooks/D02_print_environment finished
+  lrwxrwxrwx 1 root root 7 Nov 22  2024 /bin -> usr/bin
+I: user script /srv/workspace/pbuilder/4081507/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -205,7 +237,7 @@
 Get: 94 http://deb.debian.org/debian trixie/main amd64 libtext-glob-perl all 0.11-3 [7676 B]
 Get: 95 http://deb.debian.org/debian trixie/main amd64 libfile-find-rule-perl all 0.34-3 [26.6 kB]
 Get: 96 http://deb.debian.org/debian trixie/main amd64 dh-elpa all 2.1.5 [29.7 kB]
-Fetched 78.8 MB in 10s (7604 kB/s)
+Fetched 78.8 MB in 5s (15.9 MB/s)
 Preconfiguring packages ...
 Selecting previously unselected package netbase.
 (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 ... 19856 files and directories currently installed.)
@@ -624,7 +656,11 @@
 fakeroot is already the newest version (1.36.2-1).
 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
 I: Building the package
-I: Running cd /build/reproducible-path/ws-butler-0.7/ && 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  > ../ws-butler_0.7-1_source.changes
+I: user script /srv/workspace/pbuilder/4081507/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for trixie
+I: user script /srv/workspace/pbuilder/4081507/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/ws-butler-0.7/ && 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  > ../ws-butler_0.7-1_source.changes
 dpkg-buildpackage: info: source package ws-butler
 dpkg-buildpackage: info: source version 0.7-1
 dpkg-buildpackage: info: source distribution unstable
@@ -641,7 +677,7 @@
    dh_autoreconf
    dh_auto_configure
    dh_auto_build
-	make -j20 "INSTALL=install --strip-program=true"
+	make -j42 "INSTALL=install --strip-program=true"
 make[1]: Entering directory '/build/reproducible-path/ws-butler-0.7'
 make[1]: Circular show-version <- show-version dependency dropped.
 echo "*** Emacs version ***"
@@ -659,12 +695,12 @@
    dh_elpa_test
 	emacs -batch -Q -l package --eval "(add-to-list 'package-directory-list \"/usr/share/emacs/site-lisp/elpa\")" --eval "(add-to-list 'package-directory-list \"/usr/share/emacs/site-lisp/elpa-src\")" --eval "(setq ert-batch-backtrace-right-margin nil)" -f package-initialize -L . -L tests -l tests/ws-butler-tests.el --eval \(ert-run-tests-batch-and-exit\)
 Package cl is deprecated
-Running 3 tests (2025-01-26 11:02:21+0000, selector `t')
-   passed  1/3  ws-butler-test-sanity (0.010360 sec)
-   passed  2/3  ws-butler-test-trim-predicate (0.000353 sec)
-   passed  3/3  ws-butler-test-trim-predicate-nil (0.000468 sec)
+Running 3 tests (2026-02-28 17:26:23+0000, selector `t')
+   passed  1/3  ws-butler-test-sanity (0.003079 sec)
+   passed  2/3  ws-butler-test-trim-predicate (0.000162 sec)
+   passed  3/3  ws-butler-test-trim-predicate-nil (0.000172 sec)
 
-Ran 3 tests, 3 results as expected, 0 unexpected (2025-01-26 11:02:22+0000, 0.022196 sec)
+Ran 3 tests, 3 results as expected, 0 unexpected (2026-02-28 17:26:23+0000, 0.003657 sec)
 
    create-stamp debian/debhelper-build-stamp
  fakeroot debian/rules binary
@@ -694,12 +730,14 @@
 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/4081507/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/4081507/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/2139040 and its subdirectories
-I: Current time: Sat Jan 25 23:02:46 -12 2025
-I: pbuilder-time-stamp: 1737889366
+I: removing directory /srv/workspace/pbuilder/4081507 and its subdirectories
+I: Current time: Sun Mar  1 07:26:26 +14 2026
+I: pbuilder-time-stamp: 1772299586