What is the default upload-chunk-size? Does it ever get adjusted dynamically if left unspecified?

[alexklibisz]

I've observed some very strange behavior with actions/cache/save@v3. It leads me to a couple of specific questions:

1. What is the default upload-chunk-size?
2. Does the save action ever attempt to dynamically adjust the upload-chunk-size, maybe based on the cache size?

Thanks