Explanation from The Gneech
If your story is accepted for Reclamation, you grant us (The Gneech and FurPlanet) permanent but non-exclusive rights to include that story and any characters or elements you’ve created for it into the Reclamation setting and derivative works, and those elements thus become available to other creators also working in the Reclamation setting. You still own the character or element and may create works of your own with those things that do not reference the Reclamation setting.
Think of it like Into the Spider-Verse: if you write us a story about a cheetah bounty hunter named Javenar, then Javenar will always be part of Reclamation and other writers will also be able to use her in their stories, but we own A Javenar, not THE Javenar. The point is to build a sandbox with lots of cool elements for creators to play with.
This model was inspired by the Thieves’ World series by Robert Lynn Asprin. If you’re familiar with how that works, you’re good to go.