I love Seamonkey but it has been stuffed up in the last couple of years as adblock and others could not be put into extensions whatever they changed .
I used Seamonkey only for special purposes because all the bloody adds came up , my machine cpu fan came on loudly and in the background it was downloading adds flat out.!!!
I have stopped this .
UBlock Origin seems to work and works for Palemoon maybe?
To get it you need the Legacy version from https://github.com/gorhill/uBlock-for- ... -1.16.4.26 Drag it into seamonkey and voila.
Here is a bit more of a discussion on Barry's site you can read up a bit. https://easyos.org/forum/showthread.php?tid=235
Keep in mind too that the Opera browser can be downloaded free and that supplies a free VPN that protects your browsing from prying eyes. Well , I hope it does hide some.