Description is at: https://burningbecks.wordpress.com/2018/11/17/the-prusaic-extruder-x5s-goes-direct/
Note that the work this part is based on it NOT licensed permissively, but "Copyleft"!
Converted my TronXY X5S ( https://burningbecks.wordpress.com/tag/x5s/ ) with this and my old E3Dv5 to direct drive with counter-rotating "Bondtech"-style gears (clones named "btech"), after seeing this: https://shop.prusa3d.com/forum/general-discussion-announcements-and-releases-f61/new-printed-parts-extruder-version-r3-b7--t23017.html
Just realized, that the XCR-BP6 (sold as "Hexagon Hotend" on the familiar chinese shopping sites) also fits here. Not really mounted it here, but the length from J-Head Groovemount to lower end of heatsink deviates only a mm or so...