altdns 1.0.2+git20210909.8c1de0f-2 (i386 binary) in ubuntu oracular

 This package contains a DNS recon tool that allows for the discovery of
 subdomains that conform to patterns. Altdns takes in words that could be
 present in subdomains under a domain (such as test, dev, staging) as well
 as takes in a list of subdomains that you know of.
 .
 From these two lists that are provided as input to altdns, the tool then
 generates a massive output of "altered" or "mutated" potential subdomains
 that could be present. It saves this output so that it can then be used by
 your favourite DNS bruteforcing tool.