It's my opinion that this is a request for more busy work by a Proton dev instead of adding real value. That said, I'll leave it up to a Proton dev if they want to add this.
This is actually a Steam client issue. The strings in the steam client have to be updated manually by a Valve employee, and I can't do that. It's a reasonable request, but I think it probably won't happen unless their tooling gets updated to allow us to change those strings, sorry.
I just thought of something. When you install a third party proton, like glorious eggroll, it says "Proton-6.13-GE-1" in the settings menu. Now I don't know how the Steam UI works, but if glorious eggroll can include his own versioning in the release, couldn't Proton Experimental add the date versioning to its name at the end as well?
Wouldn't this not require additional changes to the Steam UI, and just add the date versioning to the end of each Proton Experimental release? It also getting it's own folder in ~/.steam/root/steamapps/common directory? Thus it overwriting the folder and updating it's name with each update.
If a date is to be added, absolutely not in that American muddle-endian format – I for one will consider use of such a format to be a bug.
It needs to be locale-agnostic (by using YYYY-MM-DD or month names or something similar) or formatted for the locale (I'm using en_GB, so I expect DD/MM/YYYY by default).
For version numbering purposes, big-endian numeric (year first) is the only sane method.
proton experimentalx2 2021-07proton 6.13-ge-1x1 2021-07
Feature Request
Description
Please consider adding version date number to Proton Experimental when selecting it in Steam settings.
e.g.
Proton Experimental (7-30-21)
Justification
This helps differentiate Proton Experimental versions more easier, instead of having to go in the log to look for the date of Experimental release. This helps everyone know what version of Proton Experimental someone is using.