Start with what the Jaguar B99 is: a 4-door saloon with 1.4 L FCA MultiAir Turbo I4, built from 2011, as electrification stopped being an experiment and the crossover took every market. What it meant takes a little longer. The shape is credited to Mike Robinson, Adrian Griffiths at Bertone.
The story
The Jaguar B99 is a concept car designed and developed by the Italian design house Bertone. It was first shown to the public on the Bertone stand at the 2011 Geneva Motor Show. The 4-door saloon was shown in two versions: compact executive (B99) and grand tourer (B99 GT). It was designed by Bertone's Michael Robinson and Adrian Griffiths and was based more on traditional Jaguars of the Geoff Lawson era compared to more recent Jaguars designed by Ian Callum.
What is underneath
The engine is 1.4 L FCA MultiAir Turbo I4. The wheelbase is 2800 mm. These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Its place in the line
The cars a buyer would have weighed it against include the Lamborghini Aventador, the Lexus LFA, the Nissan Leaf. Nearby in the Jaguar catalogue sit the F-Type and the Vanden Plas.