Display MAC in theme

[Robert LeBlanc]

I'd like to display the current MAC address (net_default_mac) on our
theme for PXE booting to help with troubleshooting. I can't seem to
figure out from the docs how to either target the text box by id and
set the text in the config file, or have a variable rendered as part
of the theme. Can someone provide a pointer here?

+ label {
  id = "host_mac"
  left = 0%
  top = 100%-25
  color = "white"
  align = "left"
  text = "${net_default_mac}"

Thank you.
----------------
Robert LeBlanc
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