See this old mozillaZine forum thread about this:

• http://forums.mozillazine.org/viewtopic.php?f=38&t=865895

(please to not post in such old threads)

See also:

• http://kb.mozillazine.org/about:config

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

The adjustment of blink rate, which is what I asked for, works fine.

The adjustment of cursor width, also given in the first link, works in the sign-in here and in this edit box, but doesn't work in the Firefox address bar or in the sign-in box on another website I just visited.

Thank you.