From the Football League website.....2019/20 EFL Trophy Rules.....
7 Players
7.1 In all rounds of the Competition a player shall be a “registered player” of his Club.
7.2 For the EFL Clubs, a registered player is one who:
7.2.1 would be registered and eligible to participate in a match in the League Competition for that EFL Club commencing at the same time and on the same date as the Match in accordance with the provisions of the Regulations; or
7.2.2 would be so eligible but for the fact that they are registered on a Long Term Loan at a club playing in the National League (National Division, North Division or South Division) but by the agreement of the Club, the National League club and the Player he has permission to return to play in this Competition.
7.3 Each EFL Club shall play its Full Available Strength in and during all Matches. Full Available Strength means the EFL Club must include at least four Qualifying Players in the ten outfield Players named in the starting eleven on the Team Sheet.
7.4 Qualifying Player means any Player who:
7.4.1 had started the immediately preceding First Team Fixture (as defined below);
7.4.2 subsequently starts the immediately following First Team Fixture;
7.4.3 is in the list of ten Players at the Club with the highest number of starting appearances in First Team Fixtures in the same Season;
7.4.4 has made forty or more starting appearances in First Team Fixtures or international equivalents (and not limited to the same Club or Season); or
7.4.5 is on standard loan from a Premier League Club or any EFL Club operating a Category One Academy.
To me this looks like rules made up by organisers who know they are running a Mickey Mouse competition.