Ore patches now spill over into the sea as submerged variants. Dredge them up with new floating hardware, and build deeper into the blue with water-placeable refined concrete.
The super inserter from Editor Extensions gets a floating variant (like all inserters) but it doesn't stay invisible in the special Testing Tools item group. It is exposed to players in non-editor mode.
Writing here because it seems to be a related bug: at least one modded inserter is being hidden by Dredgeworks: https://mods.factorio.com/mod/long_stack_inserter
While it still adds the Long Stack Inserter floating variant.
Correction, the technology wasn't researched yet. Which still means that Dredgeworks enables the floating variant before the base variant is researched.
Separate topic, and not something I will likely be changing - either I'd have to add the floating inserter to technologies that unlock the base one (which still means you can unlock them before you've unlocked flotation platforms), or I'd have to synthesize a research for each inserter's floating variation (busywork in several senses for little practical upside). It's a little wonky as-is, but it works.