I've asked a dev to create the list. It isn't in the doc (note to self: add enhancement request). I'll post the list here later today.
UPDATE: File is attached. This is valid through 10.4.0. Structure is:
object type: original WKID [authority] -> new/latest WKID [authority] Name
You'll see changes EPSG-EPSG, Esri-EPSG, EPSG-Esri
pcs: 102100 [Esri:] -> 3857 [EPSG:] WGS_1984_Web_Mercator_Auxiliary_Sphere
It also includes all objects types, including units, spheroids, etc.
pcs: projected coordinate system
vcs: vertical coordinate system
gcs: geographic coordinate system
gtf: geographic transformation
vdt: vertical datum
lin: linear unit
vtf: vertical transformation