auctex: Marking (LaTeX)
2.7.1 LaTeX Commands for Marking Environments and Sections
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-- Command: LaTeX-mark-section
('C-c *') Set mark at end of current logical section, and point at
top.
With a non-nil prefix argument, mark only the region from the
current section start to the next sectioning command. Thereby
subsections are not being marked. Otherwise, any included
subsections are also marked along with current section.
-- Command: LaTeX-mark-environment
('C-c .') Set mark to the end of the current environment and point
to the matching beginning.
If a prefix argument is given, mark the respective number of
enclosing environments. The command will not work properly if
there are unbalanced begin-end pairs in comments and verbatim
environments.