

birdtray-config.json
Edit the following strings:
"advanced/tbcmdline": [
"/usr/bin/flatpak-spawn",
"--host",
"flatpak",
"run",
"--branch=stable",
"--arch=x86_64",
"--command=betterbird",
"--file-forwarding",
"eu.betterbird.Betterbird",
"@@u",
"%u",
"@@"
],
"advanced/tbprocessname": "betterbird",
"advanced/tbwindowmatch": "Betterbird",
In Birdtray under Advanced - Thunderbird command line - call Betterbird as follows:
/usr/bin/flatpak-spawn --host flatpak run --branch=stable --arch=x86_64 --command=betterbird --file-forwarding eu.betterbird.Betterbird @@u %u @@
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