Really? That's surprising but so overkill. How does it know what files to poll and which not to, I assume file:// and localhost but more specific? Does it do it for a webpack/vite app which has its own hot reloading setup?
F5 refreshes the browser page. This has been the way to develop pages since the first browsers.
And the original question was "Import a plain js file without any node tooling and see what you get for free." You don't get hot reloading but you get all I wrote in my original comment and much more for free.
It usually goes something like this: some tool watches the file system for changes > trigger build > another tool in the chain injects changes into session > picked up by client to reflect changes, if done well without resetting state.
These are many tools in a toolchain working well together. This DOES exist in other languages, incremental builds exists. You can save and restore a binary at a certain state, and it's less hassle than it is in js.
One thing the systems development world has that I haven't seen in browser tools is radare/ghidra to follow code paths but it probably exists as a browser extension. The web is just reinventing and repackaging tools that have existed for decades.
> you get all I wrote in my original comment and much more for free
Yes, but `apt install gdb` is just as "free" as `apt install chrome` no? Everything you mentioned exists in systems development, you just haven't used it.