Hello there! This is one of these things that you should not notice unless something went horribly wrong (there is not even a build download)
When I started developing Escape from Mandrillia, I used the old SteamVR plugin that had the actions.json manifest on the game's root folder.
After updating it, the actions.json file moved to StreamingAssets (which is way tidier), but I completely forgot to update that change on Steamworks (which is a separate thing from the actual builds) Somehow, this went unnoticed because Steam must have some sort of automatic fallback. However, it seems that it can still be problematic in certain cases (with one example being a Linux user)
After this change, everything should work in most environments. If after this update your hands stop tracking or you can't access the SteamVR binding screen (even after deleting and re-downloading the game as a last measure), please report it here (if that were to happen you could also copy and paste all the text files on StreamingAssets/SteamVR to the game's root folder)