So you can use filters with it, for example 'all[width>=400][width<=600]'.
The spec string is processed using 'tokenize.tokenize' to split it in words and operators, the filters are still processed using regular expressions. This should make easier to allow grouping operators with parens.
The original test case is gone
[planetaplay/quickvid/vube] Skip inaccessible sites
Some of the songs are moved to Amazon AWS
Do not takeover soundcloud:user URLs
Add --force-generic-extractor
[noco.tv] Fix issue #6066: title interpreted as integer