A while ago we updated several wallpaper svgz images. How did we do that --- what software was used?

I updated several png images in GIT hash 49c4ccfe to fix some branding. I would like to update a related svgz, but I don't how.

The specific file to update:

tdebase/kcontrol/pics/crsc-app-background.svgz.

View tdebase/kcontrol/pics/cr128-app-background.png in the latest GIT to see how I updated that image. The svgz should look the same.

Thanks!

Darrell