The "a" signifies this is an early alpha or development version, meaning it is likely unfinished, may contain bugs, and is under active development.
Often features branching paths, character relationships, and custom CG (Computer Graphics) art. Safe Practices: SexNote-0.19.0a-pc.zip
If you can share where you found this file, I might be able to find: The Patch notes or system requirements Content warnings or story synopses The "a" signifies this is an early alpha
This is a compressed file format, meaning the contents (executable .exe file, game data, assets) must be extracted before use. Common Features of Projects in this Category: meaning it is likely unfinished