How to get dependencies and reserve dependencies for a sanp package?

I would like to know what packages a specific snap package depends on, and also to know what cased a snap package to be installed as a dependency.

In apt we can use:
apt-cache depends packagename
and for reverse dependencies:
apt-cache rdepends packagename

I would like to know what are the alternatives for snap.

many snaps ship

/snap/<snap name>/current/snap/snapcraft.yaml

that lists all build and stage packages under the parts used by the snap … (note that snap developers can opt out of shipping snapcraft.yaml though, so not all snaps ship this)

There’s also the manifest.yaml from the same directory.