The comic brilliantly parodies both Mario Bros and Linux distributions with a dash of existential crisis. The characters are dressed as popular Linux distros - Ubuntu (with its iconic circle logo) and Linux Mint (with its green "M" logo).
The joke hinges on how Linux Mint is actually based on Ubuntu, yet gets forgotten or mistaken for "Green Ubuntu" by casual users. Poor Mint is basically Ubuntu's forgotten child who just wants to be recognized for its own identity!
The Mario-style "It's-a me" speech pattern makes it even funnier, as if these distros are siblings in some dysfunctional open-source family where the derivative distro struggles for recognition against its more famous parent. Classic middle child syndrome, but with package managers!