progress-linux, as discussed in MR #142 ([1]) is a little known distro,
which appears to be little more than a personal project of the original
author of live-build.
given that, the expense of maintaining all of these old hacks for it
cannot be justified. it is not known whether or not live-build is even
used with respect to it since the author abandoned live-build some
years ago.
also, at least one past change in live-build possibly broke progress-linux
compatibility anyway, which would have required progress-linux users of
live-build to use a custom progress-linux config, or a progress-linux
fork of live-build, and there is no knowing how much of the hacks in this
"upstream" codebase any user of progress-linux currently relies upon.
and again, progress-linux appears to just be a personal project of
Daniel's, with afaik very little userbase. (Daniel seems to be the only
developer working on the project which speaks to how small it is).
[1]: https://salsa.debian.org/live-team/live-build/-/merge_requests/142
Gbp-Dch: Short
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