What Ableton Live actually changed
In Ableton's own words, Session View is where you "freely mix and match musical ideas without the constraints of a timeline". Clips sit in a grid, each track plays one of them at a time, and they can be played at any time and in any order; a whole row, a scene, launches together. The effect on a generation of producers was to make the loop, not the song, the place where music starts. That is a way of working rather than a file format, and the core of it, a loop you keep editing while it plays, needs nothing but a browser.
What genuinely does not port
Launching a grid of clips on stage from a dedicated controller, plugin hosting, Max for Live, offline work and a mature arrangement and automation environment. A browser cannot load VST or Audio Units binaries at all, and GOONS has no clip grid. If the finished record will be built in Live, a browser studio is at best where the idea started. The technical limits are on the browser-based DAW page.
Ableton's own lessons run in a browser
Ableton publishes Learning Music, interactive lessons on beats, chords, basslines, melodies and song structure that ask for no equipment and work entirely in the browser. It is not Live, but if what you want is to understand how a loop is put together, it is the official place to start, and it pairs well with the grid above.
A reasonable way to use both
Sketch in the browser, finish in Live. The loop station exports the mixed loop as a WAV file, and DrumPad and Trap Machine Pro export patterns as MIDI; Live imports both WAV and MIDI files. An idea caught on a school laptop arrives in Live as material rather than as a memory. The genre patterns are on the beat making hub.