Syntax quirks

See also: Filter performance

Filters match on word boundaries unless explicitly wildcarded
- See https://github.com/uBlockOrigin/uBlock-issues/issues/954#issuecomment-602041890
Looking-like-domain filters match only in host part of URL
- See HOSTS optimization
Negated domains in cosmetic filters work like exception (In ABP generic blocking filter overrides filter with negated domain).
- See https://github.com/uBlockOrigin/uBlock-issues/issues/388
One filter can be counted as many, example
$document works only as blocking filter
Generic cosmetic filters don't work in Shadow DOM
- See https://github.com/uBlockOrigin/uBlock-issues/issues/803
Popup filters will not close pages opened by direct user action when the page'S URL matches the link clicked
- See https://github.com/uBlockOrigin/uBlock-issues/issues/774
Domain filter in uBO matches fully qualified domain name (FQDN, these with dot at the end), where in ABP match is exact.
- See https://github.com/uBlockOrigin/uAssets/issues/7619
Simple generic cosmetic filters no longer hide <body> element after uBO v1.37.3b15
- See https://github.com/uBlockOrigin/uBlock-issues/issues/1692

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Syntax quirks

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