RimWorld makes the file format comparatively transparent—.rws saves are XML—but that does not make them context-free. A colony serializes references to the game version, DLC, mods, world objects, pawns, maps, and many definitions supplied by the active content set. SaveEditor therefore treats a proper backup as the .rws file plus environment notes. This is especially important before removing a mod or upgrading a heavily modded colony, because an XML parser succeeding does not prove that RimWorld can reconstruct every referenced definition.
For this PC reference, the documented storage is Windows: %USERPROFILE%AppDataLocalLowLudeon StudiosRimWorld by Ludeon StudiosSaves. The known file or folder pattern is *.rws; manual names plus Autosave-* records.. RimWorld saves are XML-based .rws files and embed world/colony state plus references to active DLC/mod content. The game can show the save-data location from its settings UI.
Backup guidance: Back up the entire Saves folder and also record the RimWorld version, DLC set, and mod list/load order that produced an important colony. Steam Cloud is commonly used; the official/community wiki documents platform-specific save directories. Launcher and cloud context matters because The save file is human-readable XML, but it is highly version/mod dependent. Editing XML without understanding cross-references can create a loadable-looking file that fails later.
Compatibility and recovery should stay conservative. A .rws file can be structurally valid XML yet incompatible with a different mod set or game version. Missing definitions are a compatibility problem, not automatically file corruption. If the expected progress is not visible, If a colony fails after an update or mod change, restore the save and matching mod environment together. Use the in-game “Show” save-data-location action when uncertain about the active folder. SaveEditor.com only labels a game-specific editor as available when a separate linked Tool has a verified operational runtime; this reference page by itself is not an editor claim.