diff --git a/Syntax-quirks.md b/Syntax-quirks.md
index 042a66c..c2ab213 100644
--- a/Syntax-quirks.md
+++ b/Syntax-quirks.md
@@ -10,3 +10,4 @@
     - See <https://github.com/uBlockOrigin/uBlock-issues/issues/803>
 - Popup filters will not close pages opened by direct user action
     - See <https://github.com/uBlockOrigin/uBlock-issues/issues/774>
+- Domain filter in uBO matches [_fully qualified domain name_](https://en.wikipedia.org/wiki/Fully_qualified_domain_name) (FQDN, these with dot at the end), where in ABP match is exact.
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