One of the most trouble-free developers, it is sold as a syrupy liquid concentrate that you add to water and works as a middle-of-the-road developer.

There's a lot of chemical trickery in HC-110. HC-110 is dissolved in something more akin to antifreeze than water. So if you take a piece of film and put it in the HC-110 concentrate in the bottle, it won't actually develop. There are some organic solvents and it seems to be a PQ (Phenidone-Hydroquinone) based developer, but instead of being a speed-increasing developer as compared to MQ (Metol-Hydroquinone) based developers like D-76, it's just an incredibly stable and convenient developer.