The XDG Base Directory spec covers config/data/cache/state, it does not define where executables go. Whetuu history & cache are both compliant as both go to respectively ~/.local/share/whetuu/ ($XDG_DATA_HOME) & ~/.cache/whetuu/ ($XDG_CACHE_HOME).Atuin, cargo and many other tools are doing the same. By the way, Atuin also rebinds the up arrow.