Added 2x4 For Garage Door
These two by fours were added to the garage header
to build the frame down for a new rollup garage door. This is not
something that is real common and you're not going to see it on many
homes, most garage doors are framed about an inch less than 7 foot from
top of garage floor slab to bottom of finished garage header.
This is strictly a cosmetic issue and poses no structural threat to the building. While doing a home inspection the biggest problem here will be gaps in between the two by fours and dry rot. You will run into certain cases where the two by fours were added by the garage door installer and never painted.
Note to a professional home inspector, when buying and selling a house these boards will need to be painted before the house is sold.