Diff of the two buildlogs:

--
--- b1/build.log	2024-12-19 22:39:24.640500576 +0000
+++ b2/build.log	2024-12-19 22:42:48.107262837 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Wed Jan 21 16:59:28 -12 2026
-I: pbuilder-time-stamp: 1769057968
+I: Current time: Thu Jan 22 19:02:27 +14 2026
+I: pbuilder-time-stamp: 1769058147
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/trixie-reproducible-base.tgz]
 I: copying local configuration
@@ -35,52 +35,84 @@
 dpkg-source: info: applying 0008-No-distutils.patch
 I: Not using root during the build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/2137664/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/199064/tmp/hooks/D01_modify_environment starting
+debug: Running on codethink01-arm64.
+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 Jan 22 05:02 /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/199064/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/199064/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='arm64'
-  DEBIAN_FRONTEND='noninteractive'
+  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]="aarch64-unknown-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=arm64
+  DEBIAN_FRONTEND=noninteractive
   DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=12 '
-  DISTRIBUTION='trixie'
-  HOME='/root'
-  HOST_ARCH='arm64'
+  DIRSTACK=()
+  DISTRIBUTION=trixie
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=aarch64
+  HOST_ARCH=arm64
   IFS=' 	
   '
-  INVOCATION_ID='c3ba8fb8afc042898164f2205df03dca'
-  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='2137664'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=96c58eee3afd444e9de0760ab2a8685d
+  LANG=C
+  LANGUAGE=nl_BE:nl
+  LC_ALL=C
+  MACHTYPE=aarch64-unknown-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=199064
   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.S6si9ScT/pbuilderrc_AXjO --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.S6si9ScT/b1 --logfile b1/build.log numcodecs_0.14.1+ds-1.dsc'
-  SUDO_GID='109'
-  SUDO_UID='104'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://192.168.101.4:3128'
+  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.S6si9ScT/pbuilderrc_tWqU --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.S6si9ScT/b2 --logfile b2/build.log numcodecs_0.14.1+ds-1.dsc'
+  SUDO_GID=109
+  SUDO_UID=104
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://192.168.101.4:3128
 I: uname -a
-  Linux codethink03-arm64 6.1.0-28-cloud-arm64 #1 SMP Debian 6.1.119-1 (2024-11-22) aarch64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-28-cloud-arm64 #1 SMP Debian 6.1.119-1 (2024-11-22) aarch64 GNU/Linux
 I: ls -l /bin
   lrwxrwxrwx 1 root root 7 Nov 22  2024 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/2137664/tmp/hooks/D02_print_environment finished
+I: user script /srv/workspace/pbuilder/199064/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -314,7 +346,7 @@
 Get: 144 http://deb.debian.org/debian trixie/main arm64 python3-setuptools-scm all 8.1.0-1 [40.5 kB]
 Get: 145 http://deb.debian.org/debian trixie/main arm64 python3-sphinx-issues all 5.0.0-1 [10.0 kB]
 Get: 146 http://deb.debian.org/debian trixie/main arm64 python3-zfpy arm64 1.0.1-4+b3 [137 kB]
-Fetched 63.5 MB in 1s (121 MB/s)
+Fetched 63.5 MB in 1s (116 MB/s)
 debconf: delaying package configuration, since apt-utils is not installed
 Selecting previously unselected package libjs-jquery.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
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(Reading database ... 60%
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(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 20076 files and directories currently installed.)
@@ -790,8 +822,8 @@
 Setting up tzdata (2024b-4) ...
 
 Current default time zone: 'Etc/UTC'
-Local time is now:      Thu Jan 22 05:00:11 UTC 2026.
-Universal Time is now:  Thu Jan 22 05:00:11 UTC 2026.
+Local time is now:      Thu Jan 22 05:03:15 UTC 2026.
+Universal Time is now:  Thu Jan 22 05:03:15 UTC 2026.
 Run 'dpkg-reconfigure tzdata' if you wish to change it.
 
 Setting up libpython3.13-minimal:arm64 (3.13.1-2) ...
@@ -939,7 +971,11 @@
 Building tag database...
  -> Finished parsing the build-deps
 I: Building the package
-I: Running cd /build/reproducible-path/numcodecs-0.14.1+ds/ && 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  > ../numcodecs_0.14.1+ds-1_source.changes
+I: user script /srv/workspace/pbuilder/199064/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for trixie
+I: user script /srv/workspace/pbuilder/199064/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/numcodecs-0.14.1+ds/ && 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  > ../numcodecs_0.14.1+ds-1_source.changes
 dpkg-buildpackage: info: source package numcodecs
 dpkg-buildpackage: info: source version 0.14.1+ds-1
 dpkg-buildpackage: info: source distribution unstable
@@ -1250,7 +1286,7 @@
 Copying numcodecs.egg-info to build/bdist.linux-aarch64/wheel/./numcodecs-0.14.1+ds.egg-info
 running install_scripts
 creating build/bdist.linux-aarch64/wheel/numcodecs-0.14.1+ds.dist-info/WHEEL
-creating '/build/reproducible-path/numcodecs-0.14.1+ds/.pybuild/cpython3_3.12_numcodecs/.tmp-jt6tt4nd/numcodecs-0.14.1+ds-cp312-cp312-linux_aarch64.whl' and adding 'build/bdist.linux-aarch64/wheel' to it
+creating '/build/reproducible-path/numcodecs-0.14.1+ds/.pybuild/cpython3_3.12_numcodecs/.tmp-765jkwg6/numcodecs-0.14.1+ds-cp312-cp312-linux_aarch64.whl' and adding 'build/bdist.linux-aarch64/wheel' to it
 adding 'numcodecs/__init__.py'
 adding 'numcodecs/_shuffle.cpython-312-aarch64-linux-gnu.so'
 adding 'numcodecs/abc.py'
@@ -1343,8 +1379,8 @@
 [autosummary] generating autosummary for: abc.rst, api.rst, checksum32.rst, compression/blosc.rst, compression/bz2.rst, compression/gzip.rst, compression/index.rst, compression/lz4.rst, compression/lzma.rst, compression/pcodec.rst, ..., filter/shuffle.rst, index.rst, other/index.rst, other/json.rst, other/msgpacks.rst, other/pickles.rst, other/vlen.rst, registry.rst, release.rst, zarr3.rst
 WARNING: Failed to import numcodecs.zarr3.
 Possible hints:
-* ImportError: zarr 3.0.0 or later is required to use the numcodecs zarr integration.
 * AttributeError: module 'numcodecs' has no attribute 'zarr3'
+* ImportError: zarr 3.0.0 or later is required to use the numcodecs zarr integration.
 building [mo]: targets for 0 po files that are out of date
 writing output... 
 building [html]: targets for 32 source files that are out of date
@@ -1997,7 +2033,7 @@
 XFAIL numcodecs/tests/test_blosc.py::test_partial_decode[array4-codec10]
 XFAIL numcodecs/tests/test_blosc.py::test_partial_decode[array4-codec11]
 XFAIL numcodecs/tests/test_blosc.py::test_partial_decode[array4-codec12]
-========= 768 passed, 37 skipped, 27 deselected, 36 xfailed in 18.88s ==========
+========= 768 passed, 37 skipped, 27 deselected, 36 xfailed in 28.58s ==========
 I: pybuild pybuild:334: rm -rf /build/reproducible-path/numcodecs-0.14.1+ds/.pybuild/cpython3_3.12_numcodecs/build/fixture /build/reproducible-path/numcodecs-0.14.1+ds/.pybuild/cpython3_3.12_numcodecs/build/.coverage /build/reproducible-path/numcodecs-0.14.1+ds/.pybuild/cpython3_3.12_numcodecs/build/coverage.xml
    create-stamp debian/debhelper-build-stamp
    dh_testroot -O--buildsystem=pybuild
@@ -2031,8 +2067,8 @@
 dpkg-gencontrol: warning: package python3-numcodecs: substitution variable ${sphinxdoc:Built-Using} unused, but is defined
    dh_md5sums -O--buildsystem=pybuild
    dh_builddeb -O--buildsystem=pybuild
-dpkg-deb: building package 'python3-numcodecs-dbgsym' in '../python3-numcodecs-dbgsym_0.14.1+ds-1_arm64.deb'.
 dpkg-deb: building package 'python3-numcodecs' in '../python3-numcodecs_0.14.1+ds-1_arm64.deb'.
+dpkg-deb: building package 'python3-numcodecs-dbgsym' in '../python3-numcodecs-dbgsym_0.14.1+ds-1_arm64.deb'.
  dpkg-genbuildinfo --build=binary -O../numcodecs_0.14.1+ds-1_arm64.buildinfo
  dpkg-genchanges --build=binary -O../numcodecs_0.14.1+ds-1_arm64.changes
 dpkg-genchanges: info: binary-only upload (no source code included)
@@ -2040,12 +2076,14 @@
 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/199064/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/199064/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/2137664 and its subdirectories
-I: Current time: Wed Jan 21 17:02:23 -12 2026
-I: pbuilder-time-stamp: 1769058143
+I: removing directory /srv/workspace/pbuilder/199064 and its subdirectories
+I: Current time: Thu Jan 22 19:05:46 +14 2026
+I: pbuilder-time-stamp: 1769058346