> When point is on an entry, then 'tabulated-list-print'
> moves point to the entry with the same ID.
>
> However, what ID to prefer for outline heading lines
> is not quite clear.  Possible variants:
>
> 1. The simplest way would be to remember the position of point
>    or the line number.  But this is not quite reliable
>    when new entries are inserted before.
>
> 2. Remembering the outline heading line as a string and searching for it
>    afterwards would be ambiguous when there are more headings with the
>    same string.  For example, when at the top level there are project names,
>    and at the second level mode names repeated for every project.
>
> 3. To remember a complete path like outline-hidden-headings-paths does,
>    e.g. '("Project1 name" "Mode2 name").

The third variant is implemented now.

> But this will not handle modes that don't use tabulated-list.
> For example, reverting an xref buffer with outlines now restores
> visibility of outlines, but doesn't restore point.  OTOH, maybe it's
> not responsibility of outline-minor-mode to restore point when it's
> not on a heading line.

For xref I propose a separate patch that keeps point on the same line
after reverting the xref buffer: