bp_template_include_theme_compat( string $template = '' )

function bp_template_include_theme_compat( $template = '' ) {
	// If embed template, bail.
	if ( true === function_exists( 'is_embed' ) && is_embed() ) {
		return $template;
	}

	// If the current theme doesn't need theme compat, bail at this point.
	if ( ! bp_use_theme_compat_with_current_theme() ) {
		return $template;
	}

	/**
	 * Fires when resetting main query vars and filtering 'the_content' to output BuddyPress template parts.
	 *
	 * Use this action to execute code that will communicate to BuddyPress's
	 * theme compatibility layer whether or not we're replacing the_content()
	 * with some other template part.
	 *
	 * @since BuddyPress 1.7.0
	 */
	do_action( 'bp_template_include_reset_dummy_post_data' );

	// Bail if the template already matches a BuddyPress template.
	if ( ! empty( buddypress()->theme_compat->found_template ) ) {
		return $template;
	}

	/**
	 * If we are relying on BuddyPress's built in theme compatibility to load
	 * the proper content, we need to intercept the_content, replace the
	 * output, and display ours instead.
	 *
	 * To do this, we first remove all filters from 'the_content' and hook
	 * our own function into it, which runs a series of checks to determine
	 * the context, and then uses the built in shortcodes to output the
	 * correct results from inside an output buffer.
	 *
	 * Uses bp_get_theme_compat_templates() to provide fall-backs that
	 * should be coded without superfluous mark-up and logic (prev/next
	 * navigation, comments, date/time, etc...)
	 *
	 * Hook into 'bp_get_buddypress_template' to override the array of
	 * possible templates, or 'bp_buddypress_template' to override the result.
	 */
	if ( bp_is_theme_compat_active() ) {
		$template = bp_get_theme_compat_templates();

		add_filter( 'the_content', 'bp_replace_the_content' );

		// Add BuddyPress's head action to wp_head.
		if ( ! has_action( 'wp_head', 'bp_head' ) ) {
			add_action( 'wp_head', 'bp_head' );
		}
	}

	/**
	 * Filters the template name to include.
	 *
	 * @since BuddyPress 1.7.0
	 *
	 * @param string $template Template name.
	 */
	return apply_filters( 'bp_template_include_theme_compat', $template );
}