On the CBP Carrier Information Guide, it is described as "USCIS International Operations authorization for parole". The key point is that it is listed in the CBP guide, so you can be assured that it is a valid travel document for boarding. Check here -- https://www.cbp.gov/sites/default/files/assets/documents/2019-Mar/2019 Carrier Information Guide - ENGLISH.pdf
Your wife must enter the US before the expiry date listed on the parole document. After she is paroled in, she will have 2 years of legal status in the US as a "parolee", even if she doesn't file I-485. If she had no USC immediate relatives, she would have to claim asylum if she wants to stay legally beyond those 2 years. But because she is married to you, a USC, she has a simpler and much faster path -- file I-485 (based on your marriage) to adjust status from parolee to LPR. No need to file for asylum.