again, it all says in the title. is FEbuilder restricted to only computers or is it also available on mobile devices?
No. FEBuilder (alongside most other tools we use) is a desktop application. FEBuilder in particular only works natively on Windows (so no MacOS/Linux/ChromeOS without some work either).
This question pops a lot.
Unfortunatelly, no. FEBuilder is too complex to run on phone.