What do these numbers above the terminal jetway mean for pilots?
That's a countdown to the Target Off-Block Time (TOBT) showing 67 minutes to go. The minus is like the T minus 5 for a rocket launch.

[TOBT is the] time that an Aircraft Operator (AO) or Ground Handler (GH) estimates that an aircraft will be ready, all doors closed, boarding bridge removed, push back vehicle available and ready to start up / push back immediately upon reception of clearance from the Tower. (...)
TOBTs will be displayed on the Stand Entry Guidance System (SEGS) for every flight at 'Actual in Block Time' (AIBT) or 75 minutes before a departure. The countdown clock is in line with the latest TOBT update. Please see Fig.2 [emphasis and link added]

gatwickairport.com

The display design will vary from airport to airport.
Since in your photograph there's no jet bridge (no actual docking), the display is mounted separately and is not used for parking guidance. Thanks to @fooot for identifying the airport, here's a press release on SEA's general implementation.
The guidance (and information) system at SEA (where jet bridges are used) uses &quot;infrared laser and patented 3D scanning technique&quot; to identify the plane type, distance, and orientation – unlike the older left/right parallax-based guidance.