TL;DR
In-game toggle to hide unresearched things from the factoriopediaWhat ?
Somewhere in the factoriopedia GUI, a toggle between having the factoriopedia as it currently is, and only showing recipes and items that the force has currently researched the tech for. Mods like "Recipe Book" that the factoriopedia has mostly replaced had functionality like this. This is similar in concept to the "show all items in selection list" setting, except it applies to the factoriopedia instead of selection lists.Mods like "Discovery Tree" handle this from the tech tree side, however their utility is reduced in 2.0 due to everything appearing in the factoriopedia.
Why ?
There are 2 primary reasons a player may want this.They may be playing space age or an overhaul mod and wish to avoid spoilers so that they can "discover" things as they are researched.
Players may also wish to simply reduce clutter and see what they can use an item for right now, or which machines can craft it right now.