Packaging size too large after custom engine build

I needed to build the Unreal Engine from source in order to create a Linux build and a dedicated server. However, if I create a Windows x64 development package with the engine I built from source, its size is roughly 1,2 GB. With the prebuilt engine (same version) the size is about 600 MB. This means that the custom engine build has doubled the package size, even though I did no changes to the code.

Could someone provide some hints as to what may be the cause of this large package size, and what can be done to reduce it?

The large size comes from the pak file, which is considerably larger. Does anyone know the reason for this?