I just noticed that a minor update to a Mac application is 2.5 MB larger than the previous version of the same app, and the difference is caused by the fact that Assets.car is 2,411,672 bytes in the new version and 59,665 bytes in the old version. There aren’t any additional assets in the new version, and it was built using the same version of Xcode. However, the old version was built with Xcode under Sierra (10.12) and the new version is built with Xcode under High Sierra (10.13).
The compressed file size of the new version is 16.2 MB compared with 13.8 MB for the old version.
Xcode reports its version number as: Version 9.0 (9A235)
I was wondering why this file is so much bigger under High Sierra, and I think the difference must be related to the fact that with “Base SDK” set to “Latest macOS”, the base SDK is now 10.13 rather than 10.12 - so I’m guessing that the 10.13 SDK requires larger Assets.car files for some reason...