Note: this list is generated by looking for the string for this theme hook, so it may include some references that are not actually using this theme hook.

backdrop_common_theme in core/includes/common.inc
Provides theme registration for themes across .inc files.
basis_breadcrumb in core/themes/basis/template.php
Overrides theme_breadcrumb(). Removes » from markup.
CommonBackdropSortUnitTest::setUp in core/modules/simpletest/tests/common.test
Sets up unit test environment.
CommonBackdropSortUnitTest::setUp in core/modules/simpletest/tests/common.test
Sets up unit test environment.
CommonBackdropSortUnitTest::testBackdropSort in core/modules/simpletest/tests/common.test
Tests backdrop_sort().
seven_breadcrumb in core/themes/seven/template.php
Override theme function for breadcrumb trail
system_block_configure in core/modules/system/system.module
Implements hook_block_configure().
system_block_info in core/modules/system/system.module
Implements hook_block_info().
system_block_info in core/modules/system/system.module
Implements hook_block_info().
system_block_view in core/modules/system/system.module
Implements hook_block_view().
system_breadcrumb_block in core/modules/system/system.module
Output the content for the breadcrumb block.
system_update_1025 in core/modules/system/system.install
Convert block positioning and configuration to the default layout.
template_preprocess_maintenance_page in core/includes/theme.inc
Prepares variables for maintenance-page templates.
view::get_breadcrumb in core/modules/views/includes/view.inc
Get the breadcrumb used for this view.
view::_build_arguments in core/modules/views/includes/view.inc
Build all the arguments.
ViewsBasicTest::testSimpleArgument in core/modules/views/tests/views_basic.test
Tests simple argument.
views_handler_argument::default_actions in core/modules/views/handlers/views_handler_argument.inc
Provide a list of default behaviors for this argument if the argument is not present.
views_handler_argument::init in core/modules/views/handlers/views_handler_argument.inc
init the handler with necessary data.
views_handler_argument::options_form in core/modules/views/handlers/views_handler_argument.inc
Build the options form.
views_handler_argument::option_definition in core/modules/views/handlers/views_handler_argument.inc
Information about options for all kinds of purposes will be held here. @code 'option_name' => array(
views_handler_argument::uses_breadcrumb in core/modules/views/handlers/views_handler_argument.inc
Determine if the argument can generate a breadcrumb