These are the default Liferay 6 theme variables defined in init.vm.I was searching but did not get any link ,so I hope this will help lot of people also around the globe. If anything goes wrong, pls make a comment and also try to add something that will help people around us.
## ———- Common variables ———- ##
$theme_display
$portlet_display
$theme_timestamp
$theme_settings
$css_class
$layout
$page_group
$liferay_toggle_controls
$liferay_dockbar_pinned
$css_folder
$images_folder
$javascript_folder
$templates_folder
$full_css_path
$full_templates_path
$css_main_file
$js_main_file
$company_id
$company_name
$company_logo
$company_logo_height
$company_logo_width
$company_url
$user_id
$is_default_user
$user_first_name
$user_middle_name
$user_last_name
$user_name
$is_male
$is_female
$user_birthday
$user_email_address
$language_id
$w3c_language_id
$time_zone
$user_greeting
$user_comments
$user_login_ip
$user_last_login_ip
$is_signed_in
$group_id
## ———- URLs ———- ##
$show_add_content
$add_content_text
$add_content_url
$layout_text
$layout_url
$show_control_panel
$control_panel_text
$control_panel_url
$show_home
$home_text
$home_url
$show_my_account
$my_account_text
$my_account_url
$show_page_settings
$page_settings_text
$page_settings_url
$show_sign_in
$sign_in_text
$sign_in_url
$show_sign_out
$sign_out_text
$sign_out_url
$show_toggle_controls
$toggle_controls_text
$toggle_controls_url
$update_available_url
## ———- Page ———- ##
$the_title
$selectable
$is_maximized
$is_freeform
$page_javascript_1
$page_javascript_2
$page_javascript_3
$layout
$page = $layout
$is_first_child
$is_first_parent
$the_title
$is_portlet_page
$all_portlets
$column_1_portlets
$column_2_portlets
$column_3_portlets
$column_4_portlets
$column_5_portlets
$maximized_portlet_id
$typeSettingsProperties
$page_javascript_1
$page_javascript_2
$page_javascript_3
$community_name
$css_class
$my_places_portlet_url
$community_default_public_url
$community_default_private_url
$community_default_url
$the_title
$layouts
$pages
## ———- Navigation ———- ##
$nav_items
$has_navigation
## ———- Staging ———- ##
$show_staging
$staging_text
## ———- My places ———- ##
$show_my_places
$my_places_text
## ———- Includes ———- ##
$dir_include
$bottom_include
$bottom_ext_include
$content_include
$top_head_include
$top_messages_include
## ———- Date ———- ##
$date
$current_time
$the_year