as you can see, it is going to be optional API, as evident by not already existing.

If you don't want to help lower the cost of crawling Homeservers, you won't need it. But the developers working on our Indexer are already feeling the pain of not having a way to cheaply sync with the homeserver. This is going to get way worse after users are able to migrate between servers, suddenly indexers will find themselves downloading entire user's data twice if they don't have a cheap way to recognise that they already did that work before.

wiring git in the homeserver not only not sufficient for our needs it might be more complex too.