Es3 Save Editor [best] -

By default, ES3 is in the assembly-csharp-firstpass (Plugins folder), which you can't add as a reference. Unity Discussions

: Editing a save file manually can lead to game crashes or "broken" saves if invalid values are entered. es3 save editor

Using a save editor requires a careful approach to ensure the game remains stable. By default, ES3 is in the assembly-csharp-firstpass (Plugins

Use File > Save (not Save As). The editor should create a backup automatically. Launch the game, load the save, and verify the changes. If the game crashes or the save doesn’t load, restore the backup. Use File > Save (not Save As)

Some games have dedicated GitHub projects, like the R.E.P.O Save Editor , which provide a custom interface for that specific title's save structure.

The editor window is designed to simplify debugging and manual data management during development: