Dependency based boot sequencing is the default when using sysv-rc in
Debian. The insserv program is used to order init.d scripts based on
dependencies declared in the LSB information within the scripts themselves.

Information on the LSB initscript comment convention is available from
<URL:http://refspecs.linux-foundation.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html>,
<URL:http://wiki.debian.org/LSBInitScripts> and
<URL:http://wiki.debian.org/LSBInitScripts/DependencyBasedBoot>.

To monitor the boot sequence, the bootchart2 project can be used, although
Debian packages are not currently available beyond the stretch release.

 -- Mark Hindley <leepen@debian.org>, Sat, 25 Sep 2021 17:01:28 +0100