I began my pedigree career in the late 80's early 90's.
Back then we hand wrote our pedigree charts or relied on expensive pedigree
books and custom inserts, quarterly magazines and stallion advertisements.
Nowadays you have hundreds of years of pedigree in one tap or swipe.
If you want complicated mumbo jumbo / genetic garble - I don't do that.
I'm a retired Horsewoman/Breeder with an interesting life story.
XPR cannot successfully be identified using a computer program claiming to track X-Factor.
XPR is still done the old fashioned way...custom pedigree detective work.
Pull up a pedigree - look at the individual - identify skeletal clues and start tracking backwards
Go through each generation looking for skeletal clues
Look for a recessive pattern and the expressive pattern
Yes - software speeds things up BUT, I still rely on my personal library of rare books & photos to complete the process.