That's because it's under the NFE tag. Our Strategydex only lists analyses for those fully evolved Pokemon and some NFEs that are usable in some tier, and most middle evolutions such as Vibrava are so bad that they aren't even usable in NU.
There is a message under "Pokemon" on the Strategydex page that says "Change your preferences here." Click the here and you'll be taken to this page
and from there you can change the tier threshold from Limbo to NFE.