The "cache" command:
Usage: fossil cache SUBCOMMAND
Manage the cache used for potentially expensive web pages such as
/zip and /tarball. SUBCOMMAND can be:
clear Remove all entries from the cache.
init Create the cache file if it does not already exist.
list|ls List the keys and content sizes and other stats for
all entries currently in the cache.
status Show a summary of the cache status.
The cache is stored in a file that is distinct from the repository
but that is held in the same directory as the repository. The cache
file can be deleted in order to completely disable the cache.