Firefox – How to remove a website accidentally added to Firefox’s list of HSTS sites

I host two domains on my webserver. One uses HSTS (HTTP Strict Transport Security), the other does not. My webserver was misconfigured for a short period, thereby accidentally setting HSTS on the wrong website.

This has caused my Firefox to get all confused, and it insists on accessing the site using HTTPS, which is no good.

In chrome I can inspect the HSTS status for any given domain by going to chrome://net-internals/#hsts

Is there something equivalent in Firefox? I just need to delete on entry from the list…