Canon EOS R5C Manual page 316

Setting MF Peaking (Outline Emphasis)
Edges of subjects in focus can be displayed in color to make focusing easier. You can set
the outline color and adjust the sensitivity (level) of edge detection.
1.
Select [
2.
Select [Peaking].
3.
Set [Level] and [Color].
: MF peaking settings].
Select [On].
Set as necessary.
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