Keyboard Maestro macro that displays a searchable list of headings of the current Bear note on Cmd+R. Caution: Doesn't work when the Marked app is installed, and the macro needs to be adjusted to your system.

Go to heading (Bear).kmmacros

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
	<dict>
		<key>Activate</key>
		<string>Normal</string>
		<key>CreationDate</key>
		<real>625178916.75752902</real>
		<key>Macros</key>
		<array>
			<dict>
				<key>Actions</key>
				<array>
					<dict>
						<key>MacroActionType</key>
						<string>SelectMenuItem</string>
						<key>Menu</key>
						<array>
							<string>Note</string>
							<string>Preview in Marked</string>
						</array>
						<key>TargetApplication</key>
						<dict>
							<key>BundleIdentifier</key>
							<string>net.shinyfrog.bear</string>
							<key>Name</key>
							<string>Bear</string>
							<key>NewFile</key>
							<string>/Applications/Bear.app</string>
						</dict>
						<key>TargetingType</key>
						<string>Specific</string>
					</dict>
					<dict>
						<key>MacroActionType</key>
						<string>Pause</string>
						<key>Time</key>
						<string>0.2</string>
						<key>TimeOutAbortsMacro</key>
						<true/>
					</dict>
					<dict>
						<key>KeyCode</key>
						<integer>53</integer>
						<key>MacroActionType</key>
						<string>SimulateKeystroke</string>
						<key>Modifiers</key>
						<integer>0</integer>
						<key>ReleaseAll</key>
						<false/>
						<key>TargetApplication</key>
						<dict/>
						<key>TargetingType</key>
						<string>Front</string>
					</dict>
					<dict>
						<key>DisplayKind</key>
						<string>Variable</string>
						<key>HonourFailureSettings</key>
						<true/>
						<key>IncludeStdErr</key>
						<false/>
						<key>MacroActionType</key>
						<string>ExecuteJavaScriptForAutomation</string>
						<key>Path</key>
						<string></string>
						<key>Text</key>
						<string>ObjC.import('AppKit');
function getBearHeadingList() {
	const pb = $.NSPasteboard.pasteboardWithName('mkStreamingPreview');
	const str = ObjC.unwrap(pb.stringForType('public.utf8-plain-text'));
	const lines = str.split('\n');
	const regex = /^#+\s+/;
	var headings = [];
	for(var i=0; i&lt;lines.length; ++i) {
		const line = lines[i];
		const match = line.match(regex);
		if(!match || match.length == 0) {
			continue;
		}
		const title = line.substring(match[0].length);
		const level = Math.max(0, match[0].length - 2);
		headings.push("· ".repeat(level) + title);
	}
	return headings;
}
getBearHeadingList().join("\n");</string>
						<key>TimeOutAbortsMacro</key>
						<true/>
						<key>TrimResults</key>
						<true/>
						<key>TrimResultsNew</key>
						<true/>
						<key>UseText</key>
						<true/>
						<key>Variable</key>
						<string>BearHeadingList</string>
					</dict>
					<dict>
						<key>Destination</key>
						<string>Variable</string>
						<key>DestinationVariable</key>
						<string>BearSelectedHeading</string>
						<key>MacroActionType</key>
						<string>PromptWithList</string>
						<key>NotifyOnFailure</key>
						<false/>
						<key>PromptUID</key>
						<string>7BC60A82-2B38-4A53-8552-CE172933399A</string>
						<key>Sort</key>
						<false/>
						<key>Source</key>
						<string>Variable</string>
						<key>TimeOutAbortsMacro</key>
						<true/>
						<key>Variable</key>
						<string>BearHeadingList</string>
					</dict>
					<dict>
						<key>DisplayKind</key>
						<string>Variable</string>
						<key>HonourFailureSettings</key>
						<true/>
						<key>IncludeStdErr</key>
						<false/>
						<key>MacroActionType</key>
						<string>ExecuteJavaScriptForAutomation</string>
						<key>Path</key>
						<string></string>
						<key>Text</key>
						<string>function prepareURL() {
	var kme = Application("Keyboard Maestro Engine");
	const heading = kme.getvariable("BearSelectedHeading");
	if(!heading || !heading.length) {
		return null;
	}
	const title = heading.replace("· ", "");
	if(!title.length) {
		return null;
	}
	const encodedTitle = encodeURIComponent(title);
	return "bear://x-callback-url/open-header?header=" + encodedTitle + "&amp;edit=yes";
}
prepareURL();</string>
						<key>TimeOutAbortsMacro</key>
						<true/>
						<key>TrimResults</key>
						<true/>
						<key>TrimResultsNew</key>
						<true/>
						<key>UseText</key>
						<true/>
						<key>Variable</key>
						<string>BearHeadingURL</string>
					</dict>
					<dict>
						<key>Conditions</key>
						<dict>
							<key>ConditionList</key>
							<array>
								<dict>
									<key>ConditionType</key>
									<string>Variable</string>
									<key>Variable</key>
									<string>BearHeadingURL</string>
									<key>VariableConditionType</key>
									<string>IsNotEmpty</string>
									<key>VariableValue</key>
									<string>value</string>
								</dict>
							</array>
							<key>ConditionListMatch</key>
							<string>All</string>
						</dict>
						<key>ElseActions</key>
						<array/>
						<key>MacroActionType</key>
						<string>IfThenElse</string>
						<key>ThenActions</key>
						<array>
							<dict>
								<key>IsDefaultApplication</key>
								<true/>
								<key>MacroActionType</key>
								<string>OpenURL</string>
								<key>TimeOutAbortsMacro</key>
								<true/>
								<key>URL</key>
								<string>%Variable%BearHeadingURL%</string>
							</dict>
						</array>
						<key>TimeOutAbortsMacro</key>
						<true/>
					</dict>
				</array>
				<key>CreationDate</key>
				<real>625236050.752967</real>
				<key>ModificationDate</key>
				<real>625240019.51981997</real>
				<key>Name</key>
				<string>Go to heading</string>
				<key>Triggers</key>
				<array>
					<dict>
						<key>FireType</key>
						<string>Pressed</string>
						<key>KeyCode</key>
						<integer>15</integer>
						<key>MacroTriggerType</key>
						<string>HotKey</string>
						<key>Modifiers</key>
						<integer>256</integer>
					</dict>
				</array>
				<key>UID</key>
				<string>B3859348-6123-4E34-BC70-BA6F0BEF5870</string>
			</dict>
		</array>
		<key>Name</key>
		<string>Bear</string>
		<key>Targeting</key>
		<dict>
			<key>Targeting</key>
			<string>Included</string>
			<key>TargetingApps</key>
			<array>
				<dict>
					<key>BundleIdentifier</key>
					<string>net.shinyfrog.bear</string>
					<key>Name</key>
					<string>Bear</string>
					<key>NewFile</key>
					<string>/Applications/Bear.app</string>
				</dict>
			</array>
		</dict>
		<key>ToggleMacroUID</key>
		<string>1D3C1E03-07B3-4151-8682-8973BEDD26C3</string>
		<key>UID</key>
		<string>FCA883FA-D43D-491E-A010-B4C4865040B5</string>
	</dict>
</array>
</plist>