Gimp Export Layers as PNG

If PNG is an acceptable output format, one option is to export it as Open Raster (.ora), an open specification for layered-image files.

Export Image as Open Raster (.ora)

File -> Export As ...

myfile.ora

Open myfile.ora as an archive, with a program like file-roller or 7zip.

On Ubuntu:

$ file-roller myfile.ora

(alternatively)

$ unzip myfile.ora

Windows:
Rename extension .ora to .zip and extract all.

All your layers will be png images under /data, Extract them and use at will.

https://askubuntu.com/a/749561

Sidebar in Firefox

One of the things I liked about Vivaldi is the website in sidebar. I use it so that I can compare a mobile version of a website and a desktop version side by side, often to take a screenshot.

Web page in sidebar shows mobile version,
and can be displayed next to full size

I didn't realize that you could do this with Firefox.

1. Open the page and save bookmark.
2. Open the bookmarks and right-click on the page you just saved.
3. Select 'Properties' and check 'Load this bookmark in the sidebar'

This bookmark will now always loaded in the sidebar.
You can resize the sidebar, or move to the right if that's your thing.

I create a separate folder for sidebar bookmarks, so I remember what to expect.

 Abbreviated instructions based on: https://www.maketecheasier.com/load-web-pages-firefox-sidebar/