The txtar-addmod command adds a module as a txtar archive to the a testdata module directory as understood by the goproxytest package (see https://godoc.org/github.com/rogpeppe/go-internal/goproxytest).

The txtar-c command archives a directory tree as a txtar archive printed to standard output.

The txtar-goproxy command runs a Go module proxy from a txtar module directory (as manipulated by the txtar-addmod command).

The txtar-x command extracts a txtar archive to a filesystem.