With "Allow symbol property connections", attribute mapping can be applied to a symbol in a layer, referencing each feature's unique attributes to symbolize the feature depending on them.
Eventhough those attributes are usually unique to the relative layer, for automatization it would be quite useful if it was possible to save those expressions (as a string) to a style as part of a symbol.
If the expression, after being imported from a style, then has matching attributes in the attribute table of the layer, it will work, and if it does not, the user might either receive a warning message or the symbology would stay as it would be without symbol property connections.
Like this, attribute mapping expressions (e.g., symbolization of outlines depending on the size of a feature) could be easily imported from styles and re-used in different contexts, instead of having to create them freshly every time.
