> For the complete documentation index, see [llms.txt](https://developer.thunderbird.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.thunderbird.net/thunderbird-development/codebase-overview/chat/contacts.md).

# Contacts

Contacts are at the heart of instant messaging, and thus the Chat Core has a way to abstract to a "person" (represented by an `imIContact`([git link](https://github.com/thunderbird/thunderbird-desktop/blob/main/chat/components/public/imIContactsService.idl), [searchfox link](https://searchfox.org/comm-central/source/chat/components/public/imIContactsService.idl)) instance), which might connect to multiple networks, etc.

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### Display Name <a href="#display_name" id="display_name"></a>

The display name used in the buddy list window or in conversations can come from several sources, by precedence order:

* User-set alias, stored locally (set when the user renames someone from Thunderbird)
* Server-stored alias (some protocol store the aliases online)
* Display name / Friendly name (set by the remote contact, stored on the server)
* Username, the unique identifier of the buddy for this protocol. Can be numbers (e.g. ICQ, QQ), email addresses (e.g. MSN, XMPP) or some other string.

Possible storage locations:

* mozStorage (the file blist.sqlite)
* chat core (cached copy)
* server read/write (server-stored alias)
* server read only (display names)