This is mainly adressed at authors of tooling who may rely on the output of GHCi for commands in regards to loading, unloading and reloading modules. These have changed as of ghc/HEAD to be more user-friendly.
As is also noted in the changelog, this should in theory not be anyone, as the output with the flag -fshow-loaded-modules, which is designed specifically for tooling is not affected.
The relevant merge request can be viewed here.