Achievement unlocked: entered two base64-encoded Wireguard pubkeys by hand using a phone's virtual keyboard and it worked on first try. This involved a lucky guess between a lowercase L vs an uppercase i.

There must be a better way. The Android app has a 'scan QR code' , how do I generate one from a Linux terminal?

@mgedmin i don't remember the name of the debian package, but there is a qrencode command that will give you an image you can scan
@jerojasro If I knew the text format of what the Wireguard app expects.
@mgedmin, even if it doesn't accept raw text encoded in the QR (I would try that first), you could just scan it in another app and copy that text to the clipboard.
@jerojasro
Oh it's just the config file in INI format. I don't know why I expected a URL with a custom scheme, or some openvpn-ish pseudo-XML.