curl --location --request GET 'https://testnet.koios.rest/api/v0/tx_metalabels'
<html><body><h1>404 Not Found</h1>
Requested endpoint with provided parameters was not found! Please verify syntax referring to examples from <a href="https://testnet.koios.rest">API Documentations</a> !!
</body></html>
Koios 1.0.7 - Testnet