A crafting-menu-style icon panel for hiding recipes you no longer hand-craft. Toggle the panel with the shortcut-bar button (bottom right) or CONTROL + SHIFT + H, then click recipe icons to hide/show them. Hidden recipes disappear from the crafting menu exactly like un-researched ones; assemblers already running them are unaffected. The hidden list is stored in the save, so it syncs automatically to everyone in multiplayer.
Providing the player with new tools or adjusting the game interface, without fundamentally changing gameplay.