Что протокол делает склонный - получают использование?

Кв. поддерживает несколько протоколов, перечисленных в man sources.list. Значением по умолчанию обычно является HTTP, но FTP и репозитории HTTPS также доступны. Проверьте Ваш /etc/apt/sources.list быть уверенным. Так как можно указать порты в URIs, (как deb http://foo.bar:9090/xyz ...), нестандартные порты могут также использоваться.

URI SPECIFICATION
   The currently recognized URI types are:

   http (apt-transport-http(1))
       The http scheme specifies an HTTP server for an archive and is the
       most commonly used method. The URI can directly include login
       information if the archive requires it, but the use of
       apt_auth.conf(5) should be preferred. The method also supports
       SOCKS5 and HTTP(S) proxies either configured via apt-specific
       configuration or specified by the environment variable http_proxy
       in the format (assuming an HTTP proxy requiring authentication)
       http://user:pass@server:port/. The authentication details for
       proxies can also be supplied via apt_auth.conf(5).

       Note that these forms of authentication are insecure as the whole
       communication with the remote server (or proxy) is not encrypted so
       a sufficiently capable attacker can observe and record login as
       well as all other interactions. The attacker can not modify the
       communication through as APTs data security model is independent of
       the chosen transport method. See apt-secure(8) for details.

   https (apt-transport-https(1))
       The https scheme specifies an HTTPS server for an archive and is
       very similar in use and available options to the http scheme. The
       main difference is that the communication between apt and server
       (or proxy) is encrypted. Note that the encryption does not prevent
       an attacker from knowing which server (or proxy) apt is
       communicating with and deeper analyses can potentially still reveal
       which data was downloaded. If this is a concern the Tor-based
       schemes mentioned further below might be a suitable alternative.

   file
       The file scheme allows an arbitrary directory in the file system to
       be considered an archive. This is useful for NFS mounts and local
       mirrors or archives.

   cdrom
       The cdrom scheme allows APT to use a local CD-ROM, DVD or USB drive
       with media swapping. Use the apt-cdrom(8) program to create cdrom
       entries in the source list.

   ftp
       The ftp scheme specifies an FTP server for an archive. Use of FTP
       is on the decline in favour of http and https and many archives
       either never offered or are retiring FTP access. If you still need
       this method many configuration options for it are available in the
       Acquire::ftp scope and detailed in apt.conf(5).

       Please note that an FTP proxy can be specified by using the
       ftp_proxy environment variable. It is possible to specify an HTTP
       proxy (HTTP proxy servers often understand FTP URLs) using this
       environment variable and only this environment variable. Proxies
       using HTTP specified in the configuration file will be ignored.

   copy
       The copy scheme is identical to the file scheme except that
       packages are copied into the cache directory instead of used
       directly at their location. This is useful for people using
       removable media to copy files around with APT.

   rsh, ssh
       The rsh/ssh method invokes RSH/SSH to connect to a remote host and
       access the files as a given user. Prior configuration of rhosts or
       RSA keys is recommended. The standard find and dd commands are used
       to perform the file transfers from the remote host.

   adding more recognizable URI types
       APT can be extended with more methods shipped in other optional
       packages, which should follow the naming scheme
       apt-transport-method. For instance, the APT team also maintains the
       package apt-transport-tor, which provides access methods for HTTP
       and HTTPS URIs routed via the Tor network.

Кв. - получите использование http, https или ftp (в зависимости от Вашего source.list).

Посмотрите, Как использовать https с Кв. - добираются?