Published a post on the Learn SIMS site on how I use plaintext changelogs for shared QGIS projects (with some helpful edits from a colleague).
The context is that when different people work on the same QGIS project, e.g. on Dropbox, it can be hard to tell what has changed between iterations.
I tend to save a new copy of the .qgs project file at the end of each day of working on it, with the date in the file name (in ISO format for easy sorting).
I also write a plaintext changelog file adapted from this changelog standard summarising the changes (added, changed, removed, fixed, published) and using semantic versioning to communicate the level of changes between versions.