How? is there some sort of document asserting such?
Haa its in the constitution and there was even a debate in the parliament about who can become one or not after some unknown foriegn hands were putting pressure on the government to expand it.
There is a whole video about the mps going mad at the proposal and rejecting it.
I cant find the video
I know what im saying is right but i cant find the baruuuf you seek like sources etc.

And im not going to post wiki that thing in itself currently looks suspicious

Used to be soomali now it says somali citizen under =>president of somalia => qualifications and election.
Long story short the requirements are unchanged since 1960someshi with recent fails to change it by foriegn muscles.
In other words i got nothing of what you're looking for
