Canon EOS R6 Mark II Mirrorless Camera with 24-105mm f/4-7.1 Lens - Manual (Page 486)

Manually selecting a subject for focus
1.
Check the tracking frame.
Aim the camera at the subject. An AF point (or Zone AF frame)
appears on the screen if you have set [
: AF area ] to an option
other than [ Whole area AF ]. In this case, aim the AF point over the
subject.
A tracking frame [ ] appears over any subjects detected.
Tracking frames [ ] away from AF points are displayed in gray, except
in some cases.
Once the tracked subject is near an AF point, even if it is outside the
AF point, the tracking frame turns white (distinguishing it as an active
frame), which enables selection as the main subject.
Gray display of tracking frames [ ] does not apply in movie recording.
486