Thanks! But what's being described there as "observable" is something other than the Observer pattern that "observable" comes from, which is closer to what it calls "signals". https://en.wikipedia.org/wiki/Observer_pattern
I think they are the same, Observable or Observer pattern both require a manual subscription, and publishing is done through a callback offering the latest in a stream of values.
See https://github.com/tc39/proposal-signals?tab=readme-ov-file#... for more on how signals differ.
Mainly no manual bookkeeping and the signal is kind of like a handle, and it allows lazy/computed signals that reference other signals and do the change tracking