Android
While the UX is worse, it's possible to use asbplayer on Android devices.
Many features are missing: the side panel, keyboard shortcuts, screenshots, and the WebSocket interface.
Website
The website can be used as-is. The Overlay UI will be displayed instead of the default, desktop-optimized video controls.
Extension
The asbplayer extension is availablee on the following Android browsers. As with the website, the primary way to interact with asbplayer will be through the Overlay UI.
Keyboard shortcuts and the side panel are missing, so instead subtitles are loaded by selecting the asbplayer button from the browser's extension menu.
Chromium-based
The asbplayer extension is available for Chromium-based browsers on the Chrome web store or from the releases page.
Kiwi Browser (discontinued)
Kiwi Browser is a Chromium-based mobile browser that can run extensions. However, it's development has been discontinued and the only way to install it is from the GitHub page.
Edge Canary
Edge Canary is another Chromium-based mobile browser that can run extensions. However, it is very new and there is currently little info on asbplayer's compatibility with it.
Firefox for Android
Install asbplayer from the AMO page. Firefox for Android suffers from the same limitations as Firefox - it's not possible to record audio from DRM-protected streams.