Fossa Team has updated Fossa Guard to V0.2.2 following requests from our users about extension hangs up while working with certificates issued by cacert.org.
A small investigation has been done with Certificate Revocation Lists (CRLs) available at https://isc.sans.edu/crls.html and it was discovered that CAcert's CRL is the biggest one - around 8Mb.
It contains certificates revoked since 2002 which looks reasonable only in the case when there are certificates issued for 14+ years which have a high probability of being revoked.
Unfortunately is not practical to handle such big CRLs in the browser thus we limited size of supported CRL by 512Kb to avoid time-consuming download and decoding.
So it looks like there is a strong request to implement Online Certificate Status Protocol (OCSP) support in new versions of Fossa Guard making possible to perform single certificate check if it has been revoked or not.