So, unless there is access to a magic TLO, it is not "worth" it to color code know/unknown recipes as it would take a bit of time to get it all together for all the skills every time it is run or have an option to do an initial run and then update on demand, but still little value overall. Additionally there are a lot of unlearnable recipes, so even if you made it, it still would not register.
TLDR, it has to output all the known recipes and then bounce them off the lists which only go up to ToL. To put it in perspective, just calculate the time it takes for the recipes to load for research and then add in all the other skills and that is how long you would be potentially waiting each run or on demand run
Well, upon thinking it might not be so bad, but would be I/O intensive depending on how many times run, is the value there if out of 44k recipes you know 20k but 24k are and never will be known?