[dfex]

> The technical information for this thing seems to be light on the ground. What kind of diagnostic stats are provided? How is it figuring out true Rx/Tx power without a light meter?

The programming boxes (Ubiquiti's and others) get the Rx/Tx power from the DDM (Digital Diagnostics Module) built into most SFPs - it exposes the power levels from the receiver and transmitter inside the SFP and dumps it onto an SPI bus in a standardised way which is read by the box.

> Just insert any brand’s SFP or QSFP module, select Copy, and insert any UI module to write the profile.

It's pretty common for SFP rewrite boxes to only allow writing to that particular brand's SFP modules. It's partly a sales tactic, but also often vendor "genuine" optics will ship with a write-protected EEPROM (requiring a passcode) that stops them from being written to.

If you're after something a little more "open", Reveltronics[1] make a barebones version along with software for brute-forcing EEPROM keys.

[1] https://www.reveltronics.com/en/products/sfp-qsfp-xfp