December in Servo: multiple windows, proxy support, better caching, and more

Summary

Servo 0.0.4 and our December nightly builds now support multiple windows (@mrobinson, @mukilan, #40927, #41235, #41144)! This builds on features that landed in Servo’s embedding API last month. We’ve also landed support for several web platform features, both old and new: ‘contrast-color()’ in CSS color values (@webbeef, #41542) partial support for <meta charset> (@simonwuelker, #41376) partial support for encoding sniffing (@simonwuelker, #41435) ‘background’ and ‘bgcolor’ attributes on <table>, <thead>, <tbody>, <tfoot>, <tr>, <td>, <th> (@simonwuelker, #41272) tee() on readable byte streams (@Taym95, #35991) Note: due to a known issue, servoshell on macOS may not be able to directly open new windows, depending on your system settings. For better compatibility with older web content, we now support vendor-prefixed CSS properties like ‘-moz-transform’ (@mrobinson, #41350), as well as window.clientInformation (@Taym95, #41111). We’ve continued shipping the SubtleCrypto API, with full support for ChaCha20-Poly1305, RSA-OAEP, RSA-PSS, and RSASSA-PKCS1-v1_5 (see below), plus importKey() for ML-KEM (@kkoyung, #41585) and several other improvements (@kkoyung, @PaulTreitel, @danilopedraza, #41180, #41395, #41428, #41442, #41472, #41544, #41563, #41587, #41039, #41292): Algorithm ChaCha20-Poly1305 (@kkoyung, #40978, #41003, #41030) RSA-OAEP (@kkoyung, @TimvdLippe, @jdm, #41225, #41217, #41240, #41316) RSA-PSS (@kkoyung, @jdm, #41157, #41225, #41240, #41287) RSASSA-PKCS1-v1_5 (@kkoyung, @jdm, #41172, #41225, #41240, #41267) When using servoshell on Windows, you can now see --help and log output, as long as servoshell was started in a console (@jschwe, #40961). Servo diagnostics options are now accessible in servoshell via the SERVO_DIAGNOSTICS environment variable (@atbrakhi, #41013), in addition to the usual -Z / --debug= arguments. Servo’s devtools now partially support the Network > Security tab (@jiang1997, #40567), allowing you to inspect some of the TLS details of you...