Where are the custom breakpoints saved in the site?

I used the Custom Breakpoints from within Master Addons, and couple of minutes while in the preview of my custom breakpoint in Elementor, suddenly the layout breaks apart without me having modified or touched anything, just opened the page and previewd the custom breakpoint.

The page was looking more or less OK in the specific resolution before i activated Custom Breakpoints and placed a custom breakpoint. I just wanted to retouch it. Now its all messed up at that resolution. I deleted the custom breakpoint and deactivated Custom Breakpoints, but the layout is still broken at the specific viewport. (iPhone 6/7/8 Plus, 414px)

I am suspecting that Custom Breakpoints has added some “@media” custom breakpoint code/parameters somewhere which is still there. Where can i find and clear what code Custom Breakpoints has produced related to that custom breakpoint?

Thank you