metamath binary package in Ubuntu Focal armhf

 Metamath is a tiny language for expressing theorems in abstract
 mathematics, accompanied by proofs that can be verified by a computer
 program.
 .
 This program is the reference implementation of the language. It
 provides a proof checker, a proof editor and tools to automatically
 render theorems and proofs to HTML and LaTeX files.
 .
 This package does not contain proof databases, but the tools to deal
 with them. The user can create their own databases, use those
 available on the Internet or provided by the metamath-databases
 package.

Source package