• Improved performance of computed style reads, selector matching, CSS variable substitution, CSS shorthand updates, and focus handling on pages with many style rules. (@scttcper)
• Improved performance when building detached DOM trees and reading node.isConnected. (@scttcper)
• Fixed element.tabIndex handling of invalid and out-of-range tabindex="" values to use the element's default instead of returning zero or wrapping. Values with trailing non-digits now use their leading integer, so tabindex="1e2" yields 1 instead of 100. (@rome-xi)
• Fixed CSS ident() results containing spaces or leading digits losing their required escaping during serialization and variable substitution. (@scttcper)
• Fixed 'max-lines' values combining an integer and auto to serialize with the integer first, such as 3 auto.