I can not seem to find how to make leaded glass? Am I simply missing it, or is something broken? I can see where the leaded glass can/should be used in making other things. But how to make the leaded glass itself, I cannot find?

So I found it, but shouldn't things that need it be a dependency?

If I recall from the older version of DS, the leaded glass recipe doesn't show up until after you research miners. The recipe should be available much earlier in the game, in my opinion as well, but it's not written that way. You could edit the mod "technology" file but you'd better know what you're doing.