Additional lyrebird flags not available when adding bridges

Hello. When I add a WebTunnel bridge, for example, like this:

webtunnel xxxxx xxx.xx/xxx addr=1.1.1.1 sni-imitation=apple.com

,then it's not possible to add the bridge. ("error, bridge formatting issues")

But those are additional lyrebird flags, sni-imitation changes the domain name of the connection to be able to bypass censorship better (i.e. the webtunnel bridge got blocked by SNI), or to enhance your privacy. (to better hide your Tor connection; the addr= flag caches the DNS of a bridgeline, which can be useful for privacy, or to avoid DNS spoiling in some places)

Could the problem be that WebTunnel was built from it's own repo, but not from the lyrebird repo? (the repo that the Tor Browser uses) Thanks.