To dump the content of a man-db database in text format, you can use the manconv command.
The manconv command is a utility that converts man pages between different formats and languages. It can be used to extract the content of a man-db database in text format.
Here is an example of how to use the manconv command to dump the content of a man-db database in text format:
manconv -f utf8 -T utf8 -t ASCII -l -o - /var/cache/man/index.db
This command will convert the man-db database at /var/cache/man/index.db from utf8 to ASCII format and write the output to the standard output (usually the terminal). The -l option specifies that the output should be in plain text format, and the -o - option specifies that the output should be written to the standard output.
You can redirect the output to a file if needed. For example, to save the output to a file called output.txt, you can use the > operator to redirect the output to the file:
manconv -f utf8 -T utf8 -t ASCII -l -o - /var/cache/man/index.db > output.txt
This will create a new file called output.txt that contains the content of the man-db database in text format.