I came on a site of a hospital to make some remarks:
The link email@example.com (mailto:firstname.lastname@example.org) opens a new tab with blank searching page.
No e-mail client will start.
In Chrome this link opens a same blank page, but also starts the e-mail client.
Firefox and Edge (after permission) start the e-mail client as expected.
Is this an issue of Brave and/or of this particular site.
One (more?) other site with a link mailto: I tested the e-mail client opened.
The e-mail client I use is Thunderbird.
Update Channel dev
OS Platform Microsoft Windows
OS Release 10.0.15063
OS Architecture x64