firefox-legacy-1.16.4.23

Change

• Further improve procedural cosmetic filters and operators (thanks to @hawkeye116477)
  • Support CSS selectors mixed w/ operators in procedural cosmetic filters
  • Fix and improve parsing rules from AdGuard's filter lists
  • Natively implement :nth-ancestor(n) procedural operator
  • Add :min-text-length(x) and :watch-attr procedural operators
  • Replace exec with transpose in procedural filters
• Update filter syntax converter
  • Use native implementation of :nth-ancestor(n)
  • Re-map :upward(n) from :xpath to :nth-ancestor(n)
• Replace seemingly abandoned malware lists with URLhaus Malicious URL blocklist
• Restore support for Gecko 45-50 based browsers

Note: The release notes are created/maintained by @JustOff.