This is convoluted stuff. I spend much of my work-life futzing with issues like this. A few choice blog posts/notices on the Printrbot website would go a long way to clearing things up.
There are a couple contributing problems, the first of which is the number of places that state something like
"This version is for supporting Printrboard The copy at https://github.com/PxT/Marlin
is the official source as shipped by Printrbot HQ."
That may have been true at a point in the past, but is (apparently) no longer accurate. In his videos, Brooks is promoting https://github.com/Printrbot
as the official site.
The Marlin code has a gazillion forks. This is the network chart of the Printrbot site's code: https://github.com/Printrbot/Marlin/network
You can see the fork by PxT a little ways down and by scrolling around you can see that PxT had commits as late as June 4 that haven't been committed to the Printrbot fork.
Both PxT and Printrbot were forked from Lincomatic which was forked from ErikZalm which is the top of the network (his network graph
show the terrifying number of forks out there for the unwary.)
So it's a little weird that the PxT was
the official code, but it's not where the new official code forked from. You can see who/when the contributions over the last month are coming from:
Printrbot contribs: https://github.com/Printrbot/Marlin/graphs/contributors
PxT contribs: https://github.com/PxT/Marlin/contributors
Printrbot is a lot more active and has lwalkera as a contributor. This thread notes him talking about the Printrbot fork http://www.printrbottalk.com/forum/viewtopic.php?f=22&t=2980
Here's the comparison report between the two forks we're looking at, ots of diffs:(PxT:master & Printrbot:printrbot-prod)
This site helps a little https://github.com/blog/39-say-hello-to-the-network-graph-visualizer
on explaining the network graph. It really only displays differences in code, not similarities, so it's not really a 'who-begat-who' chart. More of a 'how different have these forks gotten from each other chart.'
Warning: I'm a SVN user who s trying to wrap my head around Github and may be terribly terribly confused.
(optional Dual Extrusion) Printrbot Plus V1 [3/2013]
bed stabilizers, bed levelers, Y & X belt tensioners,
50mm fan mount, LED ring light, Z-axis screw Isolators,
Z-shaft stabilizers,optional Bowden conversion, GT2 belts/pulleys,
M8x1.25 Z Screws, Flex. Z-couplers,
RAMPS 1.4 w/ LCD,
Quick Change Extruders:
Option 1- Dual hybrid geared Wade's/Bowden w/ 3mm & 1.75mm Ubis,
Option 2 - Dual direct geared Wade's w/ 3mm & 1.75mm Ubis
Option 3 - Single geared Wade's w/ 3mm or 1.75mm Ubis
Option 4 - Single belt drive Wade's w/ E3D
MIC-6 metal bed
Thingiverse Profile: http://www.thingiverse.com/tdeagan/designs