https://www.cbr.com/luke-skywalker-y...-wars-6-cover/
Obviously sort of an in-between between the lost Anakin blue saber and his own green one.
Previous EU usually potrayed him constructing the green one as his second Saber using guidelines from Obi-Wan Kenobi's home (Which also sort of explains why Luke's saber hilt is similar to Obi-Wan's) and going on a few adventures with it. However, a deleted ROTJ scene surfaced during the blu-ray release that implied that Luke constructed the saber during the events of the movie before putting it in R2. However Marvel's own "Age of Rebellion" comics show him just prior to ROTJ using the green lightsaber. (Deleted scenes I guess are kind of shaky canon-wise anyway).
Soule claims it's mainly a homage of sorts to the first toy sabers which were yellow in color, but it's also similar to the Clone Wars Jedi Temple guards-the yellow color and the hilt are pretty much identical although this doesn't appear to be double-bladed.
Also could be kind of foreshadowing Rey's eventual custom saber a bit.