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[Jim Apple <coq-club AT jbapple.com>]

http://coq.inria.fr/cocorico/HowToContributeToTheStandardLibrary

says:

"In long proofs, use now as much as possible when a tactic closes the
current goal. This improves the robustness of the script. "

I couldn't find "now" in the index of the reference manual:

http://coq.inria.fr/refman/general-index.html
http://coq.inria.fr/distrib/current/files/Reference-Manual.pdf

Where can I find out what this tactic does?