I'm using Inkscape 0.92 on Ubuntu 19.04. I use guides very frequently. So, I tend to use File/Delete All Guides frequently to delete them all, but that requires the keyboard which slows me down quite a bit. I looked in the menu, and there is no key-binding for Delete All Guides:
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How do I create a binding as a user, without patching it into the original source and rebuilding my own local copy of Inkscape? If there is no way, then I'll file an enhancement request to have someone else who is better qualified to implement it.