Direct Out default factory setting is pre-insert, pre-EQ, pre-fade. Internal jumpers to change DO to post-EQ. Website copy: "Internal jumper plugs for pre/post-EQ aux, direct out and other options." According to the block diagram on page 34 of the manual: does the mute interrupt Direct Out even when it is set to be pre-fader?
Stereo channels (for example channels 15-16 of the 32 ch version) do not have direct outs or inserts. Instead, they have a "Stereo Channel Mic Out" jack: The output of the mic preamp is available on the MIC OUT (BREAKPOINT) TRS jack socket. This is impedance balanced and operates at a nominal 0dBu line level. Plugging into this socket breaks the signal into the associated stereo channel. In other words, this is a direct out that interrupts signal to the mix.
Available in 16, 24, 32 or 40 channel frames:
GL2400-16: 14 mono mic/line, 2 mic/dual stereo
GL2400-24: 22 mono mic/line, 2 mic/dual stereo (on channels 15 and 16)
GL2400-32: 30 mono mic/line, 2 mic/dual stereo
GL2400-40: 38 mono mic/line, 2 mic/dual stereo
The stereo input channels can be used as mono channels without losing a fader, so they are not "stealing" channels. But, these are in the middle of the board.