This program is used to share PRIVATE key with OpenKeychain.
Simply use OpenKeychain to scan the displayed QRcode, and sleect the key to import/export
NOTE: OpenKeychain work in a way that a session can be only Export or Import, while this program allow both Import and Export. If your keys does not get imported in OpenKeychain, probably is because you have imported a key. Workaround: Close the session by selecting "done" on OpenKeychain, and then inizialize a new session by scanning again the barcode.
Right now i'm waiting for an official answer from the original author, https://0xacab.org/dkg/openpgp-skt/issues/3
The idea would be main code in GPL3 and utils in LGPL, and to move those utils library in dedicated repository