This is not a problem with readthedoc, it is a problem with how firefox handles redirects.
xrst is using a redirect in the index.html file to load any page that one chooses on the command line; e.g.,
```
<html><script>
window.location.href="user-guide.html"
</script></html>
```
The problem is that once firefox gets the redirect it never reloads it when it changes.
I had to clear my cache to get it to reload.