can't create .php files for plugin addon but can create .sdij files

I'm using scorehud on pocketmine and trying to add addons.

Since there is no way to import files except for worlds, I was thinking of just creating a file and putting the code in it.

For the addons, it is a .php file but when i try to create it, nothing happens.

I can create everything else

Is it that its a glitch or am i missing something.

Thanks

Yes json works, you can even type random letters and it works

Quote from Roman

This is intended.

is there a reason for this?

also is there an alternative way to add the addons for ScoreHud