Libr....: we are confident of the first three letters and if the fourth is r rather than a (note that RNGCL cites Libanius) we can see no possibility other than that this is a contraction of Liber-. Of the cognomina listed in NPEL and RNGCL, Lib(e)ranus, Lib(e)ratus (or -ius), Lib(e)rarius and Lib(e)rinus, the last seems to us least awkward for both front and back.
Veranio: there is very little trace of the last letter but it may have an apex mark over it, as may the following suo. The first five letters are reasonably secure and Veranius is attested as a cognomen (for an occurrence at Trier see CIL 13.11888); Cleranius is also attested (see RNGCL) but only as a gentilicium.
..bi: tibi is what we might expect but the second letter looks like a clear e and sebi looks like a plausible reading (cf. 184.ii.22 etc.).
The traces are not substantial enough to enable us to suggest a reading. Their position implies rather a large gap on the front above the first line, which is odd.
The traces at the left are compatible with a Librino. The following letters presumably belong to his title or position, perhaps beginning with a centurial sign and followed by a name of 5 or 6 letters of which the second may be x.