As described (but never very succinctly) in
the League press release, the ECHL's "season-ending roster" rule is simply a way for a team to extend their rights to a small collection of players into the summer. This allows extra time for the teams to flesh out their next season's roster possibilities without losing potentially key players to other League teams in the process. I reckon the feelings of the players on these lists will be mixed, depending on whether they wish to continue with their 2021-22 team or whether they want to jump to another team for 2022-23. The players not on a list are free agents, unless they are still under a rare multi-year contract (if those even exist any more in the ECHL).