How I made Firefox much faster with an Estonian ID card

I haven’t blogged in almost ten years, wow. This time I discovered something that I think deserves a blog post.
I have an Estonian e-Residency because I speak Estonian and visit quite often (at least when there’s not a pandemic going on). My default Firefox profile is easily more than 10 years old. With the Estonian ID card inserted into a card reader, Firefox has always been very slow with that profile, pretty much unusable.

With a fresh Firefox profile everything has worked very well, there’s a bit of slowness that I can see when browsing with the ID card inserted compared to when the card is not in the reader, but it’s not significant. Today I wanted to register as a reader at the Tallinn Central Library, because they offer Estonian e-books that I would like to read. Having to open a fresh Firefox profile to browse a library web site irritated me enough that I started looking for a solution. I found the solution by reading the CAC page of the Arch wiki.

I went to Edit -> Settings -> Privacy & Security -> Security Devices. I saw that my old profile had both “OpenSC PKCS” and “OpenSC PKCS#11 Module” in there. The fresh profiles did not have the “OpenSC PKSC” entry. So I removed that one and now the browser works faster.

I typically use Finnish on the desktop, just because I believe everyone should be able to use free and open source software in their native language. I’ll attach a screenshot, which is in Finnish. The entry marked with a square is the one I had to remove. I’m using Firefox 93 on Fedora 35.