MBS used to ship a quicklook plugin for macOS so you could look at the version of Xojo a project was created with
Under Sequoia that no longer works 
And Apple changed the API in a way that Christian hasn’t remittent the plugin
In the mean time if you HAVE MBS plugins I have taken their Service example and made a system service that lets you see what version the project is saved from.
This works for text, binary & xml projects.
The project is available on my Github
To build an executable you will need an MBS license
Then to update and enable the service run the following commands in Terminal
/System/Library/CoreServices/pbs -update
/System/Library/CoreServices/pbs -dump_cache
And once you do this you’ll see when you right click on a Xojo project file
