for: https://html5test.com
add to Opera this features

elements:
Text-level semantic elements:time element; data element
Interactive elements: menu element of type toolbar; menu element of type context

forms:
input type=file: Directory upload support

video:
Audio track selection
Video track selection
Video codecs: MPEG-4 ASP support; H.265 support
Audio codecs: Dolby Digital support; Dolby Digital Plus support

streaming:
DRM support
Adaptive bit rate: Dynamic Adaptive Streaming / MPEG-DASH; HTTP Live Streaming / HLS
Codecs: MP4 with H.265 support; TS with H.264 support; TS with H.265 support
Audio codecs: MP4 with Dolby Digital Plus support; TS with AAC support; TS with Dolby Digital support; TS with Dolby Digital Plus support

2d graphics:
Features: Hit testing support
Image export formats: JPEG-XR support

3d and vr:
VR Headset: WebVR

streams:
Writable streams

peer to peer:
Connectivity: ObjectRTC API for WebRTC
Input: Screen Capture

user interaction:
Drag and drop: Attributes: dropzone attribute

security:
Authentication: Web Authentication / FIDO 2

payments:
Web Payments

web applications:
Content and Scheme handlers: Custom content handlers

files:
Accessing the file system: FileSystem API

scripting:
Script execution: Script execution events
ECMAScript 6: Modules
webaseembly: dartwebaseembly