Hardware Support for Web-Based PIC Microcontroller Development

These programmer devices are hardware peripherals. So as a web-based tool, MPLAB Xpress would not be able to utilize them without installing additional software to bridge the gap. This is counter to the "Xpress" goal of offering zero-install, low barrier to entry into the world of PIC.
Microchip Technology's solution to this challenge is to create "MPLAB Xpress" branded evaluation boards with programmer hardware already on board. This specific product line is designed to eliminate the need for specialized devices or driver software, because it talks to the connected computer as a USB flash storage device. As far as the PC knows, this evaluation board is just another USB flash drive, which the PC knows how to access it without special drivers.
Customers with these evaluation boards could write a PIC program in their web browser with MPLAB Xpress and build the program into a binary file that the browser downloads. The downloaded file can then be copied to the evaluation board just like copying to a USB flash drive. Then the user presses the reset button on the board and the PIC16F18345 starts running the program.
An interesting side note: how did Microchip implement a PIC programmer that accepts compiled binary code via USB flash storage? They did it with another PIC. The evaluation board has two PIC chips on board: One is a PIC16F1454 always running the USB storage and programming functions. The other is the PIC16F18345 chip we're actually writing code for.
So this is why the name of the cloud-based tool is in the name of this piece of hardware. This line of evaluation boards have been specifically designed to support the cloud-based tool, making it possible to get started writing code for PIC chips without installing any software.