Serial Clock Line (SCL); provides a clock signal that synchronises communication between your Raspberry Pi and an I2C device; this pin has a 1.8 kΩ on-board pull-up resistor to 3.3 V
Feeding 5V into GPIO pins: GPIO logic is 3.3V and not 5 V tolerant (source)
Back-powering through the USB ports while also powering via GPIO pins 2 and 6: avoid back-powering through the USB ports (source)
Assuming the header is pre-soldered: the 40-pin GPIO header is unpopulated (source)
What we could not confirm
40-pin header: pin names are the GPn names as printed on the official page; the alternate-function table is not covered (only GP2 and GP3 functions are given).
Specs come from the store listing; the official product specification page for this model is not covered.
Typical current draw: not stated in an official source.
Max current per GPIO pin: not stated in the official source.
Building with the Raspberry Pi Zero 2 W? Describe your project on Soldr: it assigns pins from the board's published pinout, checks power and logic levels, and shows how to wire every part.