The maintainers are generally available in Slack at
https://cloud-native.slack.com/messages/flagger/ (obtain an invitation
at https://slack.cncf.io/).

In alphabetical order:

Stefan Prodan, Weaveworks <stefan@weave.works> (github: @stefanprodan, slack: stefanprodan)
Takeshi Yoneda, Tetrate <takeshi@tetrate.io> (github: @mathetake, slack: mathetake)
Sanskar Jaiswal, Weaveworks <sanskar.jaiswal@weave.works> (github: @aryan9600, slack: aryan9600)