Debian relies on external entities for these things:
SSL CA auditing (Mozilla)
SSL certificate signing (Let’s Encrypt)
Tor network for onion services
- Free Software community for new contributors and upstream development
Copyright aggregation, license enforcement (Software Freedom Conservancy)
- Various services to block email/wiki/etc spam
IRC network (OFTC)
IP addresses (hosting partners, AMPRNet, DG-i for 2a02:158:ffff::/48)
DNS registrar (Gandi)
HTTP CDNs (Fastly, CloudFlare, CloudFront, LeaseWeb, CD/archive/video mirrors)
BitTorrent tracker and CD/DVD/BD image storage (ACC, Umeå University)
BitTorrent network for CD/DVD/BD image distribution
Physical network for CD/DVD/BD distribution (vendors)
Debian machine hosting and donations, DebConf infrastructure sponsors
Funding (donors, financial partners, annual DebConf sponsors)
Asset holding (Trusted Organisations)
Paid support and development (pre-installers, consultants and development partners)