I also needed to access the GAS environment on mobile, mainly to edit triggers.
A cumbersome, but nonetheless working way of doing this is:
- use your mobile chrome browser;
- go to https://script.google.com while logged into your Google account on your phone;
- you can access the GAS environment there.
It's very cumbersome to use it this way, but it works.
I, once logged into my own account environment, bookmarked the page for easy access later, should I ever need it.
I don't recommend editing any code this way. In fact, avoid it.
However, this approach could be useful if, in a bind, you ever need to manually run a code (run) from the editor, or if you need to edit the triggers, the latter being my case.