Nothing in the wiki or recent expert takes mentions a recent concussion test or injury for Jaxson Dart in 2026. The only concussion info on file is that he dealt with them during his 2025 rookie season — the wiki notes it as an "early durability concern" heading into this year (from the Jaxson Dart page).
That said, the 2026 Giants coaching staff (John Harbaugh, Matt Nagy) is actively working to reduce Dart's designed rushing role by ~50% to protect him from hits and prioritize his health, which suggests they're mindful of his concussion history.
If you saw a specific report about a recent concussion test, it may have broken after the wiki's last update — I can't confirm it from what's in here. Want me to check for any other Giants QB news?