As per a tweet by Guillermo Tomoyose, this feature has been spotted on Windows 10 on WhatsApp. The same has been corroborated by WABetaInfo again announcing, “WhatsApp is rolling out WhatsApp Beta calls on WhatsApp Desktop for more users!”
WhatsApp is rolling out WhatsApp Beta calls on WhatsApp Desktop for more users!https://t.co/4EduW4bHfP https://t.co/JIFRFLB8je
— WABetaInfo (@WABetaInfo) 1611252824000
To recall, this was revealed back in December by WABetaInfo that some users are seeing calls button in the chat header on WhatsApp Desktop.
Back then, WABetaInfo had released a web version 2.2037.6 of the WhatsApp Web platform. As part of this report, WABetaInfo had claimed that WhatsApp is still working on developing this feature, therefore they are under development stage and not yet available to all users on WhatsApp Web and Desktop update.
Now, the feature seems to be rolling out in a staged manner and the global rollout is expected to happen soon.