The Rc.xml file contains many of the configuration options for Openbox, it is located at ~/.config/openbox/rc.xml, and is accessible from the main menu under Preferences → Openbox Config → Edit rc.xml. Many of the more common options can be configured using the GUI application obconf, accessible through the main menu under Preferences → Openbox config → GUI Config Tool, Keybindings are covered on another page DESKTOP Configuring Keybindings.
The File is well commented and fairly self explanatory.
The first section (up to <keyboard>) mainly covers the same things that DESKTOP Obconf does.
<resistance>
<strength>10</strength>
<screen_edge_strength>20</screen_edge_strength>
</resistance>
strength is basically the number of pixels that you need to drag a window before it will cover another window. screen_edge_strength is the same but for the screen edge.
See the Openbox Configuration page for more info.
The second section within the
<keyboard></keyboard>
tags deals with keybindings. The section within the
<mouse></mouse>
tags deals with mouse bindings.
See DESKTOP Configuring Keybindings for more information.
The next section deals with the main menu and its behaviour
<menu>
<!-- You can specify more than one menu file in here and they are all loaded,
just don't make menu ids clash or, well, it'll be kind of pointless -->
<!-- default menu file (or custom one in $HOME/.config/openbox/) -->
<!-- system menu files on Debian systems
<file>/var/lib/openbox/debian-menu.xml</file>
<file>debian-menu.xml</file> -->
<file>menu.xml</file>
<hideDelay>200</hideDelay>
<middle>no</middle>
<submenuShowDelay>100</submenuShowDelay>
<applicationIcons>yes</applicationIcons>
</menu>
<file> is the menu that is used, by default menu.xml. <hideDelay> if a button press lasts longer than this the menu is closed (in milliseconds). <middle> whether to centre submenus relative to the main menu, or not. <submenuShowDelay> delay for showing submenus <applicationIcons> whether to show icons in the menu.
For more information on modifying the actual contents of the menu see DESKTOP Configuring the Openbox Menu.
the section within the
<applications></applications>
tags.
This section deals with rules for individual windows, whether to hide window decorations, start maximised etc, the rc.xml has a well annotated example.
See this page in the official Openbox documentation for more information.