Paper filing W2

[CuriousWhale]

When you mail a paper tax return does the IRS hand input your W2 information by hand?

was always curious how this happens since they would have to have the records in the system to satisfy their matching program

[Critter-3]

The IRS gets the W-2 information from the SS administration off the W-2 the employer filed and the paper copy you send is not "entered" in the system but is simply used to verify the information you entered on the tax return form 1040  matches what they already have on file.  

[CuriousWhale]

If the information from the paper w2s is never entered into the system then how does the IRS matching program run to check each EIN vs the documents filed by the tax payer?