.stsync was just an idea of me. By default in every peer I suggest for all operational files and directories, e.g.
.stfolder .stversions .stignore .syncthing. *. *. tmp ~ syncthing ~ *. *. tmp . . .
to set up a system directory with the suggested or another name. This would have the advantage of a clear location or easier handling, e.g. in IgnoreLists etc., etc.