First appearance of the Blight in print.
This version of the Legion Constitution is adapted from Legion of Super-Heroes, The (DC, 1980 series) #308-310 with the following changes: minus clauses 1.4, 2.5, 3.1 (i), 3.7, and 3.10 (iii), clauses 2.1, 3.4, 3.5, 3.13 and 5.6 are edited; new inserted 5.7 and 5.8; clause 7.11 has been modified with the postboot Legionnaires named.
The Table of Contents says this is adapted from Who's Who in the Legion of Super-Heroes (DC, 1988 series) #2-6, but the information there is extracted from four years earlier as shown here in the reprint notes (the edits are new here except for the missing 3.7). And much of the information was published in tidbits in even earlier stories, and in places such as Adventure Comics (DC, 1938 series) #325-326 and Legion of Super-Heroes #1 (February 1973).
The writer is listed in issues 308-310 as Paul Levitz, and the 2008 reprint also lists him, but it's likely someone else added the new clauses (this issue doesn't list a writer).
The table of contents calls this "Interview with United Planets President R.J. Brande", but it very obviously has a title on the sequence itself.