The usecase driving [fossil]'s ability to nest the checkout of one repository into the checkout of another was that we (the Tcl Maintainers) wanted to share the same tclconfig/ across many packages instead of maintaining actual copies per package.

A concrete example of this can be found at
[http://core.tcl.tk/thread/wiki?name=Tracking+Thread+Sources%|%Tracking Thread Sources]
with '''tclconfig''' nested into a checkout of package '''Thread'''.

Generalized the setup looks like shown below, with the package INNER nested into the checkout of OUTER.

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# Start with a regular checkout of a project OUTER

% mkdir outer
% cd outer
% fossil open /path/to/outer.fossil

# Then add the INNER project
# Remember, we are in .../outer here

% mkdir inner
% cd inner
% fossil open --nested /path/to/inner.fossil

# Note the --nested option in the last command. This is necessary to make this work.
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