Ligatures could probably be simply shown by adding one or two of the most common ones ( <=, != etc...)
Maybe it's changed in the last hour or two, but for me it does indicate when ligatures are present -- in the list on the lest, under the name of each font there's a line giving name, date, and some features -- one of which is "ligatures".
Fonts with ligatures are indicated as such, but I’ve yet to add all the other metadata. I do have the data, just need ideas on how to surface it in the UI with too much clutter. I also have to add search, keyboard navigation, etc. I’ll probably have things to do here well beyond retirement ;)
It might be nice to include some detail as to the features provided by some of the fonts on the font list, if it can be done without making the UI too busy.
I'm thinking indicators for things like: true italic provided (instead of leaving the OS to use false italics), true bold provided, programming ligatures (as seen in those like Fira Code), ... Perhaps filters too.