Texas Instruments E5420 N-Channel JFET TO-92

Manufactured by Texas Instruments - Part # E5420 - TO-92 through hole package

I have not been able to find any data relating to these transistors apart from an old Texas Instruments blog. TI couldn't find any reference to it in their archives and expected it was manufactured pre 1970. My component tester says it is an N-Channel JFET (see photo) and the person searching for info was trying to replace one in an audio pre-amp.

If anyone has the spec for this I would appreciate it.

Brand new old stock