Is this some sort of rofi fallback visualization?

[dentex]

Hi.
I'm recently experiencing probable X11 crashes on a raspberry pi 4 running Debian bookworm with i3 desktop. After a few minutes from boot, the hdmi output goes black. If I start rofi, the video comes back with a white background and I see some strange circles. See pictures. I think it might be rofi in some sort of fallback or test mode due to X11 crashed, but I'd like to know if this is the case or if anyone has ever seen something similar. Thanks.

(Rofi v. 1.7.5)

[DaveDavenport]

that looks like i3lock.

[dentex]

Thanks... that was it. I still don't know how it got enabled it, but I'll figure out something. Thanks again for the solution.