For #8668 (develop command), higery has written code that reuses install_distinfo to create the dist-info dir in the build dir.  It requires #12344, which I will commit when Thomas has time to finish his patch.  We also need to make install_distinfo more flexible: For example, on #12279 we discussed about the RECORD file, which should be empty when created by the test command (nothing is installed), and we mentioned RESOURCES, which should probably be created, with relative paths.  (The resources API is intended to work with zero config in a source checkout or unpacked tarball, even though it currently doesn’t, but given that test runs in the build dir, we’re not in the source dir anymore, so RESOURCES should probably be written.)