KevinTheJedi The admin told me this:
"The PHAR extension is installed, yes, and should just work on our hosting. But I also know that loading websites from a PHAR ca be a bit finicky with paths, I definitely wouldn’t recommend it.
Another thing to consider is that we do not provide command line access or the ability to run commands on our hosting. So if you’re looking to run a command line tool like Composer (which is also a PHAR), then you can’t use it because of that."