This is a proposal to avoid serving CN banners to known bots/crawlers.

The reasons being:

• banners are by nature temporary content, that could be incorrectly taken into account for content indexing (see itwiki blackout disaster as an example of this sort of thing going wrong and being very hard to undo)
• the common method for banner injection is detrimental to metrics like Cumulative Layout Shift that Google is now focusing on, because content is pushed down when banners are inserted: https://web.dev/vitals/
• by not serving banners to bots, we will get more accurate engagement metrics for the banners (a bot might follow banner links and affect CTR metrics)
• a bot is never going to donate money or participate in Wiki Loves monuments