Looks like RelEng could do with some direction from us?
I talked about this with @Jdrewniak @pmiazga @Niedzielski and we have decided to remove this from MobileFrontend. We think the library is useful as it makes sure your extension.json has correctly listed its dependencies correctly (e.g. catches cases where you forgot to add your messages to the ResourceLoader module) however it does a lot of stuff that we no longer need (e.g. check dependencies using M.require) and requires a lot of investment that is not valuable enough to give.
The above patch removes it from MobileFrontend and should be seen as permission to remove anywhere else in the Wikimedia stack.