To go along with this, you would want a way to reset the prefix.
+1 to this. It would be really, really useful if we had a button "Reset compatibility data" in Properties > Local Files.
Reasons:
1 - I keep messing with my game's prefixes (especially the non-silver ones), and resetting it became common action;
2 - I once lost some unimportant saves because I deleted the compatdata before the wineserver properly closed. And then the Steam Cloud synced... Having a button correctly constrained could avoid this;
3 - We may want to re-run the dependencies installation after wine/proton/game updates.
To go along with this, you would want a way to reset the prefix.
+1 to this. It would be really, really useful if we had a button "Reset compatibility data" in
Properties > Local Files.
Honestly, a command line would be okay for now. I suspect changing the Steam GUI for Linux only is a very rare occurrence and in this case a blocker.
[...] the intent of Steam Play is for an entry-level user to be able to use the features.
After quite a few lengthy discussions I tend to disagree. The intent of Steam Play is for an entry-level user to be able to run a supported Windows-only title on Linux out of the box, not to tinker around Wine/Proton options. Wine was never intended for end-users but for maintainers (i.e. tech-savvy people who know what they're doing) who'd wrap packages in Wine prefix for the end-user to install and run with minimal effort. There's even a Wine library that developers can compile into their Windows source thus creating a Linux pseudo-native build. Therefore, I think taking that responsibility away from developers (and maintainers) and putting it on the end-user is against the intent of Wine, so (probably?) against the intent of Steam Play and Proton as well. It also takes away the incentive from the developer because why would they bother building and testing for Linux if Linux users are told tinker around on their own. On top of that, adding menus / buttons / anything visual / git-related will confuse a common user who doesn't even understand what Proton is.
I agree a tool can exist but with intent to be used by a tinkerers and not common end-users, i.e. I disagree it should be a visual addition to Steam client. IMHO protontricks is enough for tinkering and the only missing part is prefix reset that could be solved by adding a CLI flag to Steam client on Linux (which is more plausible and requires less green-lighting than a visual change anyway).
If you really want something that helps the end-user with games that aren't already officially supported by Steam Play then something like "Lutris for Steam" would be a way to go, i.e. a database of peer-reviewed scenarios where tech-savvy people could add a per-game install script and Steam would use it automatically without end-user having to do anything. It might even use Lutris scripts directly because why not. The only issue here is security, i.e. some authoritative body (either trusted users or Valve employees) would have to decide which install scripts are safe to use and don't e.g. install backdoors or download licensed binaries (although that last part could be mitigated by notifying the end-user that Valve can't be held responsible for external Steam Play install scripts).
If some game requires also on Windows some library, then installing it by game should also (t)its library in its game folder and use it(and I think that Steam already do this).
But there are a lot of Windows XP, Windows 7, Windows 8 games which under Steam are already unsupported due Steam is unsupported and Windows 10 is also by Microsoft near end of support... Therefore some thinking about this is viable for Valve. Microsoft has builtin support for running under older version of Windows, but such feature is too crappy and Linux is in better shape for support although maybe Virtualization of Windows XP is doable, but doing such thing for running some obsolete game is big no no for me and making it run in modern environment cost $, but that is not my problem when also some crappy Steam Linux Client could run it without problem, maybe :)
Winetricks/Protontricks download some MSFT things, which may be no longer accessible as hackish way to do things not longer possible...
Can this issue be closed now that Steam has an option to reset the prefix?
use protontricks instead of winetricks for Steam, if allowed that hack try and disaster instead of native Steam options.
Nothing extracted yet.
While its quite easy to installing things via winetricks (point it towards Proton and the prefix) the intent of Steam Play is for an entry-level user to be able to use the features.
Therefore I suggest a dialog of the most common winetrick work arounds (ie --force xact, dmusic, . . .)
To go along with this, you wou'd want a way to reset the prefix. Currently you either need a back up copy, or you need to move the game directory, uninstall it, move it back and reinstall. I would suggest Git as a back end for reverting these changes (which is what I've been doing).
I have compatdata as a Git repo and moved the default Proton prefixes (3.7.3 and 3.7.4) in there and have them symlinked into their normal spot. You could give every game its own branch for easy reset (I don't, but I think it might be useful for an automated process to better handle multiple prefixes).
It would add and commit changes before and after doing something like apply a winetrick or updating to a new version of Proton. This also requires that user data is symlinked to their homefolder other wise saved games will get wiped in the process, but that is an existing request (I think) so no reason to repeat it.
You need the before and after to weed out those changes that occur during normal usage, such as saving games. By having a before and after (as opposed to just one of those) you can accurately revert the changes.