[Media] what is this (...).long-type-(...).txt thing?

(i'm on termux, and farcli is a single .rs file compiled with rustc, if it matters)

it randomly appears out of nowhere with another number in the name, and contains only the name of a type (i guess one that the compiler infers my program uses? idk)

this time it's:

Index<std::ops::RangeFrom<Option<usize>>>

but last time it appeared it was different

what is this? what does it do? why does it just appear out of nowhere from time to time?