According to Blocky’s test logs, restricted access initially began no earlier than March 8, 2022 and no later than March 19, 2022.

Users report: https://bgme.me/@bgme/107986773834355287 Testing results (by blocky.greatfire.org)

Before: https://blocky.greatfire.org/api/url_test_result/18800410?format=ooni

After: https://blocky.greatfire.org/api/url_test_result/18861443?format=ooni

Firefox starts blocking uBlock Origin and other ad-blocking add-ons in China on addons.mozilla.org

Affected add-ons that are known to be restricted