Solo isn’t Han’s first brush with a prequel: George Lucas considered having a 10-year-old Han Solo cameo in Revenge of the Sith. Though he decided against it in the end, the idea made it as far as a draft of the script and approved concept art.
Way back when a Han film was just a rumor, /Film pulled the scans and this Iain McCaig quote:
It’s not in the script anymore, but we were told that Han Solo was on Kashyyyk and that he was being raised by Chewbacca. He’s such a persnickety guy later on – he always has to have the best of everything – so I thought it’d be great if when he was a kid, he was an absolute slob.
From the script:
HAN SOLO: I found part of a transmitter droid near the east bay… I think it’s still sending and receiving signals.
YODA: Good. Good. Track this we can back to the source. Find General Grievous, we might…
As someone who found even having Chewbacca in Sith a bit on-the-nose, I’m glad this didn’t go forward. But it’s an interesting bit of info to amaze and astound your friends, assuming they’re not the type to peruse 13-year-old concept art books or follow dozens of movie sites.