[erlang-questions] Cover compiling a release?

[Roger Lipscombe]

We deploy a multi-node Erlang release to our staging environment,
where we run a bunch of Python-driven end-to-end tests.

I'd like to extract code coverage metrics, so we can figure out (a)
whether we're missing any test scenarios, and (b) whether we can just
delete a bunch of unused code.

So: is there a way to compile an Erlang release (we use relx via
erlang.mk) with coverage enabled, such that I can (e.g.) rpc into the
node and gather coverage data for later analysis?