twitter, bsky, misskey and bilibili each carried enabled() -> true,
media_headers(url) -> None and is_retryable(err) -> the trait's own default,
with no caller outside their tests (the adapters never override those
methods, so the default was already the production policy). The tests that
only restated the default are gone; the two that pin site-specific classes
(bsky's MediaPrep, bilibili's risk-control codes) now ask the Site impl, and
site/mod.rs keeps one assertion of the shared retry policy. The live
verification notes (no Referer needed for hdslb/twimg) survive as comments.
Fourth site adapter: POST /api/notes/show, renote-aware caption and
media normalization, DriveFile type → Illustration/Animated/Video.
Empty thumbnailUrl strings filtered out in thumbnail_for.