Obsessive and Quirky
Tabaxi have an innate obsessive curiosity fixed upon something specific, be it a monster, magic item, legend, or location. On top of this, they possess a personality quirk that can fit in their Flaw box on their character sheet. Volo's Guide to Monsters has a table for this, or you may of course create your own.
First-party traits for the Tabaxi can be found on page 113 of Volo's Guide to Monsters and is copyright Wizards of the Coast.