[PROJ] Intermediate steps due same datum transformation

[Oleg Bizin]

Hi,

I want to clarify for myself the question about the work of the library
under the hood.
I have a lot of work with QGIS which uses the library as a reprojecting
mechanism.

When there is reprojection between CRS with  the same datum, is the
intermediate transformation of datums to wgs84 used as an intermediate step
or not?

For example, if I project data from *EPSG 4284 Pulkovo 1942*   to* EPSG
28411 Pulkovo 1942 / Gauss-Kruger zone 14 *which both on Pulkovo 42 datum
the pipeline looks like this?

 EPSG 4284 > WGS84 > EPSG 28411

or in case of custom CRS like this:

+proj=tmerc +lat_0=0 +lon_0=xxxx +k=1 +x_0=xxxxx +y_0=xxxx +*ellps=krass
+towgs84*=25,-141,-78.5,0,0.35,0.736,0 +units=m +no_defs

 here I see an explicit to WGS clause

Or in this case  intermediate steps to the universal WGS 84 are not
performed?

Thanks!
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