This file is indexed.

/usr/share/doc-base/apt-user-guide is in apt-doc 1.4.9.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
Document: apt-user-guide
Title: APT User's Guide
Author: Jason Gunthorpe
Abstract: The APT User's Guide provides an overview of how to use the
 APT package manager, and provides a detailed look at the apt-get tool.
Section: Debian

Format: html
Index: /usr/share/doc/apt-doc/guide.html/index.html
Files: /usr/share/doc/apt-doc/guide.html/*.html

Format: text
Files: /usr/share/doc/apt-doc/guide.text.gz