tramp-temp-name-prefix

tramp-temp-name-prefix is a variable defined in `tramp.el'.
Its value is

"tramp."

• This variable may be risky if used as a file-local variable.

Documentation:
Prefix to use for temporary files.
If this is a relative file name (such as "tramp."), it is considered
relative to the directory name returned by the function
`tramp-compat-temporary-file-directory' (which see). It may also be an
absolute file name; don't forget to include a prefix for the filename
part, though.