Canon WFT-R10 Advanced User's Manual page 73

Note
When the camera is set to record RAW images to either the CFexpress or the SD
card and JPEGs or HEIF to the another card, specify which images to transfer in
the [RAW+JPEG transfer] or [RAW+HEIF transfer] setting. Also use this setting
when RAW+JPEG or RAW+HEIF images are simultaneously recorded on a single
card.
The captured images are also stored on the card.
If images of the same size are simultaneously recorded on two cards, the images
recorded on the card that is preferentially specified in [ Record/play] or [
Play] under [ : Record func+card/folder sel.] will be transferred.
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