Hover any inserter (or inserter ghost) to see its maximum throughput in the entity tooltip: items per second with research hand-size bonuses, quality, circuit/manual stack limits, belt stacking and belt speeds taken into account.
Providing the player with new tools or adjusting the game interface, without fundamentally changing gameplay.
Fridges for Space Age that slow spoilage without removing the challenge. Cold chambers need water and vent steam that has to go somewhere; cryo vaults are cold for free on Aquilo and run on Aquilo-charged cryo cells everywhere else; refrigerated wagons run off their equipment grid; a cryo press seals food in ice blocks for the trip between planets.
Mods introducing new content into the game.