Come Grellard enhanced the LedgerHQ/wallet-api repository by developing new features for the Account Request API, focusing on improving onboarding flows and debugging visibility. He introduced a useCase parameter to the account.request API, allowing for more precise control over onboarding scenarios. Additionally, he implemented an areCurrenciesFiltered flag within the account.request wallet handler, which indicates whether currency filtering was applied during account requests, aiding in transparency and troubleshooting. Working primarily with TypeScript and leveraging his expertise in API and full stack development, Come delivered targeted improvements that addressed specific workflow needs, demonstrating a focused and methodical engineering approach within a short timeframe.