This 2019 era editor still works on my Fender Mustang Version 1 usb modeling amp, 
search in synaptic for mustang-plug. The screenshot has a distortion before the amp, followed by tremolo, delay, and reverb. The panels can be sized and placed as needed. The order of the four possible effects appears to be limited, noisy things first, then modulations, then ambience. There may be issues with newer xcb versions. I had one crash where xcb was prime in the terminal output.
Fender made 5 usb amp models, I, II, III, IV, and V. These are old by modern $tandard$, but still sound great, and prices should be between $50 and $250.
- Mustang-Plug in AVLinux.jpg (182.05 KiB) Viewed 3066 times
The III, IV, and V have 100 preset slots on a main dial, and all fx/amp parameters are accessible from a small screen.
The V 5 is a head only, came with a sometimes troubled complex footswitch, and it has fx send/returns. An optional 4x10 cab was sold with it sometimes.
The V4 is the same engine but with a 2X12 cab configured in stereo, and with fx send/returns, the most expensive model, these days.
The V III has the same engine, in a 1X12 cab, and fx send/return, probably the most popular version
The I and II versions differ in the speaker and cab, and each have 24 preset slots, with color coded lights, 8 each of yellow green and red, on the main dial. Only the modulations and reverbs were selectable (by dials) on these. But each group of 8 has the amps in use printed by the selector dial. They sell in the $50 to $120 dollar range. On these, only the last 16 presets could be edited, which is where the Mustang Plug software shines, as it allows full editing of everything on the least expensive amps, as well as on the bigger amps. This benefits all users amps liking to edit by computer. There are bias, sag, usb-gain, and other controls in advanced mode.
All the above amps also became available in V2 iterations, like 'Mustang IV Version 2, with some nice improvements, but I don't think the editor works with them. But as mentioned in the nearby Fender LT25 topic, they all show up in qjackctl, and can be used extensively with whatever software you connect them to in the patchbay. Like a Fender classic preamp, or a glorified pedalboard. Finding a bargain in either case, should be pretty easy.