in owners-common/src/main/java/com/googlesource/gerrit/owners/common/AccountsImpl.java [141:152]
private boolean isFullMatch(Account.Id id, String nameOrEmail) {
Optional<AccountState> accountState = byId.get(id);
if (!accountState.isPresent()) {
return false;
}
Account account = accountState.get().account();
return isFullNameMatch(account, nameOrEmail)
|| nameOrEmail.equalsIgnoreCase(account.preferredEmail())
|| accountState.get().externalIds().stream()
.anyMatch(eid -> isEMailMatch(eid, nameOrEmail) || isUsernameMatch(eid, nameOrEmail));
}