We can see that the security-state/intermediates takes quite a while to synchronize (between 1.7s and 6.5s for 75% of our users, more than 18s for 5% of them).

The total collection size is 1268KB. Will it continue to grow? How big?

Could we ship a JSON dump of the data in mozilla-central [1] so that users only download what's been changed recently?

[1] https://firefox-source-docs.mozilla.org/services/common/services/RemoteSettings.html#initial-data

I would love to do that. IIRC some collection of us talked about this in Mozlando and the issue was the attachments, that there wasn't a way to ship those yet?

The growth is going to be very slow. We average adding < 25 new entries per year.

For that particular collection the size of the records list itself is pretty big, so shipping the dump will help greatly, especially if the collection does not change much as you said.

Currently there is no way to ship attachments in m-c indeed, but it could be a nice addition! I'll create a ticket :)

Ship Remote Settings dump for security-state/intermediates

https://hg.mozilla.org/mozilla-central/rev/92392a781212