Glad to meet a another tinkerer!
Playing around with this on my Glo (2.1.5), I didn't see an "AutoFrontLightOffMinutes" item, just "AutoOffMinutes."
This latter attribute is where the "Automatically turn off after" choice from the power option of the "Light, Sleep & Power" settings menu lives. For example:
AutoOffMinutes=0 equates to the "Never" setting
AutoOffMinutes=45 equates to "45 mins"
Based on this, and since the behavior for sleep mode is to come back up with the last light setting, I'm guessing this tweak is just bypassing the light-killing power-down. Great if it gets you what you're after – the light back on! But is your Glo actually powering down? (Not that it matters, just hacker curiosity.)
And my device doesn't have the exact "AutoFrontLight
OffMinutes" attribute in the config file. Are we on different SW versions? Did you add that in yourself? Does something else make it write that in?