I probably should have been more clear. To me it looked like there were big mineral deposits that were blocking the weep holes. It may have been the way the photos looked. I wouldn't stick any wires up more than an 1/8" or so.
I think the holes might be weep holes for the shower glass?
Issaquah Tile Installation
Issaquah Bellevue Seattle
The poster is from California. Most likely a large wide mouthed cast iron clamping drain tied into a hot mop as the primary waterproofing system. Tried and true system that has worked for decades. That shower looks pretty fresh and perhaps it was given a face lift and screwed up before the original poster bought the place.
I'll be interested to see how it turns out now that the silicone has been removed from the weep hole area.