Panel from Psi-Force #20 (June 1988), script by Fabian Nicieza, pencils by Ron Lim, inks by Mike Witherby, colors by Nel Yomtov, letters by Rick Parker
To be fair to the script, it's referring to the 1988 fictional death within the New Universe of Mark Gruenwald when Star Brand blew up a Pittsburgh comic book convention, not Gruenward's real-world passing in 1996. Within the pages of the New U, John Byrne and Howard Mackie got exploded too.
I like to think that within the New U, their ashes were mixed into the printers' ink that made Captain America. And DC put John Byrne's ashes in the ink for Superman. In other words, the world outside your window.