yes, i looked at that spec. any application that sets XDG_DATA_DIRS should ensure that the default paths are included in the list. i have no argument with that.
what i was trying to get at was: installations of exaile may break if a prefix is used that is not in the list of xdg defaults.
for instance, if i installed exaile under the /opt directory, it would not find the plugins in /opt/share/exaile/plugins because /opt/share is not one of the default xdg data directories. (of course, some other application may have added it).
should users be able to choose where to install exaile? if so, at the very least, the installation instructions should include a warning about the possible consequences of doing that.