According to the author xdg 3.0 requires ruby 2.6.3 so this port should depend on lang/ruby26 and not lang/ruby25.
Just for a note, lang/ruby26 is still experimental and have some issues such as bug 237833.
(In reply to serpent7776 from comment #0)
I know that port requires ruby 2.6.3. I did simple test against ruby 2.5 and it works, therefore I patched it to use ruby 2.5. I did further test for this PR, it does not fully work with ruby 2.5. I'll mark it BROKEN for ruby 2.4 and 2.5.
This port has been marked BROKEN for ruby 2.4 and 2.5 in r504908.
You could build this port with ruby 2.6 as default ruby version.