Changes to parsing metadata from filter lists · 2018-09-17 15:00 by Sebastian Noack
Filter lists may contain a set of special comments providing metadata. In the past, those special comments could be given at any position in the filter list. Starting with Adblock Plus 3.4 (and developments builds as of 126.96.36.1995), special comments must be given at the top of the filter list, right below the header, otherwise they will be ignored (issue 6923). This allows Adblock Plus to parse filter lists more efficiently (since it doesn’t have to check anymore whether every single line may contain any metadata). The new semantics, also make it easier for tools like python-abp to reliably recognize metadata.
Checksum special comment is no longer supported (issue 6849). In fact, checksums weren’t verified anymore since Adblock Plus 3.0 for Firefox, and never were verified on any other browser. The usefulness of such a checksum is extremely limited in modern days. Filter list authors may want to remove the checksum (if any) from their filter lists. Doing so is backwards-compatible since checksums never were mandatory.
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