You can clone with
HTTPS or Subversion.
As reported here http://stackoverflow.com/questions/13405651/markerfacecolor-ignoring-saturation-value-python-matplotlib
plt.errorbar(1,1,1,markerfacecolor=[1,0,0,0.1], color=[1,0,0,0.1], marker='o')
produces a marker with alpha = 1
plt.errorbar(1,1,1,markeredgecolor=[0,1,0,0.1], color=[1,0,0,0.1], marker='o')
produces markers with the specified alpha.
tested on 1.3.x (9f2cb13)
possible fix: 5f5a677e00e162b63935e3b4364c843c7f1bac7c
I put in a pull request, but mucked up linking it to the issue
added change log entry for #1504 and #1505
Fixed by #1505