Legal Definition of ‘ne varietur’
: it must not be changed —used as an inscription on notarized documents especially that are evidence of an encumbrance (as a mortgage)
‘...by virtue of a power of attorney dated [ ] 2013 (which after being signed ne varietur shall remain attached to the present deed to be submitted together with it to the registration formalities).’

(https://www.proz.com/kudoz/english-to-russian/law-general/5305852-signed-ne-varietur.html)
ne varietur initialling

QUICK REFERENCE
Initialling by the negotiators of a treaty, or parts thereof, indicating that the text is authentic, but that their governments are not to be considered bound, thereby allowing further time ...

From:  ‘ne varietur initialling’ in Encyclopaedic Dictionary of International Law »
Subjects: Law — International Law