Why is package 'xul-ext-ubufox' is required to install the Firefox package?

Question

When trying to install the Firefox package on Ubuntu 14.04 it prompts me to also install xul-ext-ubufox:

$ sudo apt-get install firefox
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  xul-ext-ubufox
Suggested packages:
  ttf-lyx
The following NEW packages will be installed
  firefox xul-ext-ubufox

Why is the Ubufox package required to install the Firefox package? As I understand, Ubufox only extends the features of Firefox, so it should be a suggested package, not a required one.

And a side question, how can I install Firefox without installing Ubufox?

Solution

Summary:

If you want to install a package (here firefox) without automatically having to install its recommendations (here xul-ext-ubufox), you must use apt-get's --no-install-recommends parameter:

sudo apt-get install --no-install-recommends firefox

Detailed explanation:

The package xul-ext-ubufox integrates Firefox better into the Ubuntu OS in several ways. It is a recommended package of firefox, according to the (shortened) output of:

$ apt-cache show firefox
Package: firefox
Priority: optional
Section: web
Installed-Size: 100442
Maintainer: Ubuntu Mozilla Team <[email protected]>
Architecture: i386
Version: 40.0+build4-0ubuntu0.15.04.1
Replaces: kubuntu-firefox-installer
Provides: gnome-www-browser, iceweasel, www-browser

Depends: lsb-release, libasound2 (>= 1.0.16), libatk1.0-0 (>= 1.12.4), libc6 (>= 2.17), libcairo2 (>= 1.2.4), libdbus-1-3 (>= 1.0.2), libdbus-glib-1-2 (>= 0.78), libfontconfig1 (>= 2.9.0), libfreetype6 (>= 2.2.1), libgcc1 (>= 1:4.1.1), libgdk-pixbuf2.0-0 (>= 2.22.0), libglib2.0-0 (>= 2.31.8), libgtk2.0-0 (>= 2.24.0), libpango-1.0-0 (>= 1.22.0), libpangocairo-1.0-0 (>= 1.14.0), libstartup-notification0 (>= 0.8), libstdc++6 (>= 4.9), libx11-6, libxcomposite1 (>= 1:0.3-1), libxdamage1 (>= 1:1.1), libxext6, libxfixes3, libxrender1, libxt6

Recommends: xul-ext-ubufox, libcanberra0, libdbusmenu-glib4, libdbusmenu-gtk4

Suggests: fonts-lyx

Filename: pool/main/f/firefox/firefox_40.0+build4-0ubuntu0.15.04.1_i386.deb
Size: 42549576
[...]

I tried to highlight the important lines for you by separating them with blank lines. A package may ask for other packages in 3 ways: It can depend on, recommend or suggest them.

• Dependencies are required for a package to run and must be installed anyway. There's no way around this.
• Recommendations are packages that should usually also be installed along with the main package, but are not highly required to run. You might omit them if you want, but by default apt-get installs them as if they were true dependencies.
• Suggestions are not installed automatically, they just get displayed and you might consider installing them manually yourself if you want.

As xul-ext-ubufox is a recommended package of firefox, apt-get wants to automatically install it when you try to get Firefox. To stop this behaviour, you must use the following command, which disables the automatic installation of recommended packages for this single time:

sudo apt-get install --no-install-recommends firefox

Comments

[RonnieDroid]

ubufox is a package that adds extra features to Firefox in Ubuntu. to make it more integrated to it. so you need it.

[jangorecki]

@RonnieDroid I know what is ubufox. Why should I need it? If I want just firefox and not integration features then I simply not need it, therefore the question, please try to stick to the question.

[saiarcot895]

Strictly speaking, you don't need it. If you run apt-cache show firefox, you should see that xul-ext-ubufox is listed under Recommends, which means it will (likely) be installed by default, but you can remove it afterwards without removing Firefox.

[jangorecki]

@saiarcot895 any way to install without installing the Recommends package?

[saiarcot895]

You can either run sudo apt-get install --no-install-recommends firefox, or sudo aptitude install firefox xul-ext-ubufox_ (this tells Aptitude to install firefox, but purge xul-ext-ubufox), or use the ncurses version of Aptitude to select firefox, but unselect xul-ext-ubufox.

[retorquere]

It makes it "more integrated" in what way? From what I can tell, it changes my startup page -- that's not the kind of "more integrated" I want.

[Kevin]

In practice, recommends are often de facto dependencies, and skipping them may only make sense for highly specialized installations. But that's not the case for the ubufox extension.