These cleanups were added in 2016. Every converted system has executed
these by now.

This reverts commit 152c5b8.

This migration script was first added in 3.7.5, released in late 2019.
All computers that shipped with the configuration this migration script
updates must have booted with this script at least 3 times – final 3.9
release, final 4.0 release, and final 5.1 release – before they reach
6.x, so this script has had at least 3 (and more likely hundreds) of
opportunities to run.

This reverts commit 753e3e7. As its
message says:

> After a checkpoint we can drop this script and unit.

This commit was first included in 5.0.0 but it was backported to 4.0.10
as 6c9ea9a. So all systems running
Endless OS 6 have passed through 2 checkpoints; and the eos4.0
version of eos-updater checks that this configuration field is set
before allowing the system to update to 5.x.

This reverts commit 7aece6f and
commit c3ad579.

This one-time migration script was included in eos4.0 when we
standardized on driverless printing. Any computer running Endless OS 6
which was originally installed with eos3.x has booted at least the final
4.0.x release and the final 5.1.x release, so it is guaranteed that this
script has been run.

This reverts commit dc15364 and commit
8d8ba8f.

This hook was added in order to support the companion app helper
service, which made the content within knowledge apps accessible on the
local network, to be consumed by an Android app we commissioned.

We removed the companion app helper service from the OS many moons ago.

A bit of archaeology first!

This tmpfiles.d snippet was added as part of our Endless Key V1 work, in
commit 13aca9c. The rest of that commit
was reverted in commit fd5bb2e but this
file was left in place (without being installed).

Commit
1e369f4 then started installing it
again, along with some code that would add an override at
/run/flatpak/overrides/org.learningequality.Kolibri when booting the
Endless Key V1 system. This was first shipped in Endless OS 3.8.6.

I removed that in commit 0aefc1b
(shipped in Endless OS 5.0.0) but missed this file.

Unfortunately this snippet was not running only on the Endless Key V1
environment, but on every Endless OS system that booted any version
since 3.8.6 and before 5.0.0. So a large number (probably the majority)
of Endless OS systems now have a symbolic link at
/var/lib/flatpak/overrides.  This is kind of bad because it means
`flatpak override --system` doesn't persist across a reboot.

Stop creating the symbolic link, and its target in /run; then clean up
the dangling symbolic link. Unfortunately tmpfiles.d has no directive
that specifies “delete a dangling symbolic link” so we have to write a
cleanup unit to do that.

We can drop the cleanup unit after the next checkpoint.

https://phabricator.endlessm.com/T35475

The service that used this stamp file was removed in
e009273.

All current systems have had ample opportunity to clean up these stamp
files.

This was for the EC100 which we have long since discontinued.

https://phabricator.endlessm.com/T5226