Related discussion:
https://github.com/ameshkov/diffupdates
The benefits of diff-patching filter lists is much shorter update
schedule and significantly less bandwidth consumed.
At the moment, only default filter lists are subject to be
diff-patched.
External filter lists can make their lists diff-patchable by
following the specification link above.
Only filter lists fetched by the auto-updater are candidate for
diff-patching.
Forcing a manual update of the filter lists will prevent the
diff-patcher from kicking in until one or more lists are
auto-updated.
Some back-of-the-envelop calculations regarding the load on free
CDN solutions used by uBO to distribute its own filter lists:
Currently, for each CDN (with lists updating after days):
~560 M req/month, ~78 TB/month
With diff-patching lists on a 6-hour schedule:
~390 M req/month, 1 TB/month
Those estimates were done according to statistics shown by
jsDelivr, which is one of 4 CDNs picked randomly when a list
updates:
https://www.jsdelivr.com/package/gh/uBlockOrigin/uAssetsCDN?tab=stats