@BW_controlroom
You are right, Google (as several web map providers do) uses the
"WGS 84 / Pseudo-Mercator" projection.
It uses the Mercator "spherical" formulas, that is, formulas written to project a SPHERE, for projecting the WGS84 ELLIPSOID. This is done for saving calculation time and resources.
In other words, the Google Maps projection is an adaptation of the Mercator projection, with some little error more than the original.
https://en.wikipedia.org/wiki/Web_Mercator_projection
If you go to http://www.epsg-registry.org/ , and paste
WGS 84 / Pseudo-Mercator
in the search field, you find a rigorous description of that coordinate system.

@BW_controlroom
You are right, Google (as several web map providers do) uses the
"WGS 84 / Pseudo-Mercator" projection.
It uses the Mercator "spherical" formulas, that is, formulas written to project a SPHERE, for projecting the WGS84 ELLIPSOID. This is done for saving calculation time and resources.
In other words, the Google Maps projection is an adaptation of the Mercator projection, with some little error more than the original.
https://en.wikipedia.org/wiki/Web_Mercator_projection
If you go to http://www.epsg-registry.org/ , and paste
WGS 84 / Pseudo-Mercator
in the search field, you find a rigorous description of that coordinate system.