Neat tool! One thing to note, the
config.yaml also contains the salt used for the hashed user passwords, so if that's gone it's no longer possible to log in without running the first run wizard again. It might be interesting to maybe instruct the user to extract that from the file ("looks like this") or maybe even try to grep for it if the file is not completely broken. The field in question is
Also something to note, OctoPrint will automatically generate a new
config.yaml when there isn't one yet. So in case of corruption just renaming/removing the broken one should get you back a working state, and I think even a possibility to reset user authentication (I might be mistaken though and will check that, and if it's not yet the case also rectify it). Of course that will mean having to set up everything again.