The bot added the meta label to nodejs/node#11583, which as far as I can see didn't touch any of the files specified in lib/node-labels.js#L10-L11, which is:
[/^([A-Z]+$|CODE_OF_CONDUCT|ROADMAP|WORKING_GROUPS|GOVERNANCE|CHANGELOG|\.mail|\.git.+)/, 'meta'],
AFAICT this matches ALLCAPS or something that starts with one of the listed words in the root.
Looks like meta labelling was added in #37 so cc/ @Fishrock123
