I have recently added a free DNS wildcard SSL to my domain using certbot/dns-route53. SSL and HTTPS are working perfect, but I just have one concern. In the process of getting the certificate, I was given DNS TXT record values for each of my domain and subdomains and asked to add the records to my Route53 hosted zone. I thought these values should be secrets and should not be shared or exposed to anyone. However, if I just go to this link "https://toolbox.googleapps.com/apps/dig/#TXT" and type out my domain like _acme-challenge.{my-domain}, it shows exactly what the record values are for each of my domain and subdomains.
What are these TXT record values for and are they safe to be exposed? If not, is there any way to forbid the access to these values?