what is this?

[AC Question]

170618 01:24:37.230-0500

 

[Tim1954]

We need context. Where are these numbers?

 

[ManiacJoe]

It looks like a timestamp formatted as
yymmdd hh:mm:ss.fff-zzzz
where fff is the fractions of a second and zzzz is the +/- timezone offset from UTC.