All that is truly known of The Johnnies is that they were a 20 amino acid lifeforms in the standard temperature and pressure ranges. From artifacts, other than Appleseeds, attributed to the Johnnies, they appear to be humanoids with three fingers and two opposing thumbs and bicameral vision. Since the last Johnny was alive nearly 4.5 billion years ago, the scarity of artifacts is acceptable even for a starfaring species.
Johnnies were responsible for the Appleseeds that set the bio foundation for most of habitble planets in the Alpha Regions of Known Space and possibly beyond. Because of them, there is as much life as there is in the region.
Zenologist believe that Life was such a sacred gift to them, that they felt it their worshipful duty to make sure the gift would be passed on to as many as possible. This prompted them to uplift the Elventi and Spiralians and make the universe more habitable.
The origin of the name comes for a mix of Real and Legendary Sources from Sol III. This is where Dr Yallan, who provided definitive proof of the existance of Appleseeds and Johnnies long before the discovery of an Appleseed, did his ground breaking work in the field of ectogenophylic materials.
Note: Only one Appleseed has ever been found. This unit was damaged by an asteroid collision in the warp belt of the Cyrell System. It has floated there for 3.5 billion years until recently discovered by the Confederation Fleet Ship Inspiration. It was only after that discovery that several truly ancient artifacts were attributed to the Johnnies, due to their matching spectral composition of their Neutronic Steel.