What to put in stable for projects without a stable branch? Use the master branch? Use the release tar? Include nothing and confuse people who are using stable?
Also I suspect we have lots of people using dev/stable who expect it to be stable when in reality it's stable-branches-that-need-testing. I wonder if we should rename to beta since those branches are often used for betas (such as with Plasma).
I believe it could be useful under the condition that it would be an add-on repository for release/user. We could then utilize it to build beta's and RC's, optimize packaging and have people testing the betas/RC's without too much risk.
What to put in stable for projects without a stable branch?
there is no such thing. every project releases from some branch, that branch (e.g. master) is then equal to a dedicated stable branch... just in case you didn't know, that's why kf5 builds have no stable variant, as their unstable variant gets simply pushed into stable
Also I suspect we have lots of people using dev/stable who expect it to be stable when in reality it's stable-branches-that-need-testing.
open a separate task for separate stuff
That's conceptually and technically a different thing (i.e. closer to how release builds work than dev builds). That's a different discussion though. The purpose of stable is to CI next-stable such that we can quickly iterate a release build out of that. If you feel a beta repo is a thing we should have, please start a task for it. We discussed this originally but it never materialized since it basically was blocked by release build tech and then some.
uses master branches as appropriate
rename it to testing
https://phabricator.kde.org/T4893