value is obsolete

(only used in obsolete function getResonatorLatLng)

I was figuring it might get (mis)used in add-on scripts. Ought to either get changed or removed, though.

This is modified in Leaflet v1.0.0:
Leaflet/Leaflet#4184

@nhamer This value has a long history of wanting to be edited, so we should probably document the source path of the value. @McBen is right when stating it serves almost no useful purpose in core atm. This value has historically mirrored the value on the stock Intel Map, as to not lose it. The math around fixing these differences is too big for the scope of this post, except to say retaining stock Intel's opinion on the value is important, stock Intel still has the best accuracy rating on edge case links. And their opinion? 6378137.

When I first started contributing to this project I went through the same process on this constant, as others have. So I propose something different. How about we rename it to "STOCK_INTEL_EARTH_RADIUS" or something similarly self-documenting?

@FesterCluck I prefer clean code. Maintain (or talking) about unused/obselete code is just a wasted of time.

The source path of the value is Leaflet 0.7 stock, 6367000 is the correct value.

@McBen could we just remove (internal) users of it then? layer_farms_find.user.js uses its own version of the value (as does the china map offset, but that's almost certainly correct for the purpose)

I wrote something long, and then just realized removing it might be best. If we're worried about plugin authors, we could write a getter for the value that spits out warnings of deprecation to console for a while, then just remove it.

@FesterCluck, @nhamer

This value has a long history of wanting to be edited, so we should probably document the source path of the value.

Could you explain it here?
What are the purpose of changing the value?
What is proper value of it?
Where is the source of S2 value? Is it really used in Ingress backend?