~/.config/
is indeed the default directory for XDGBDS, however this path does not prove that the specification is respected.
If it is, then the config path is $XDG_CONFIG_HOME/Vessel/
.
If it is not, then the value of XDG is not the right one (Template:XDG).
Furthermore, the Save game data location path ~/.minecraft/saves
shows us that the game does not respect the XDGBDS.