I've added a number of mods using the links from here:
in the same way I did before, but none of these mods are avaliable for me to add to my mod pack. I've also found mods in the STEP build (which have a WIKI page) that are also not showing up at all.
This can be seen when you go to a mod pack, click the "edit modlist" button.
Then click the "add another" button.
Even though the mod has been added, and has a wiki page, it will not show up, and can't be added. Therefore the mod pack can't be updated with new mods.