diff --git a/.browserslistrc b/.browserslistrc
index 635fdf53ffa..573c97e9e9c 100644
--- a/.browserslistrc
+++ b/.browserslistrc
@@ -1,2 +1,4 @@
 defaults
-ie >= 11
\ No newline at end of file
+not ie > 0
+not ie_mob > 0
+not dead
\ No newline at end of file
diff --git a/babel-plugin-expose-private-functions-and-variables.js b/babel-plugin-expose-private-functions-and-variables.js
new file mode 100644
index 00000000000..f0807e3397b
--- /dev/null
+++ b/babel-plugin-expose-private-functions-and-variables.js
@@ -0,0 +1,87 @@
+// eslint-disable-next-line no-undef
+module.exports = function ({types: t}) {
+
+	function createNestedMemberExpression(identifiers) {
+		if (identifiers.length === 1) {
+			return t.identifier(identifiers[0]);
+		} else {
+			const [head, ...tail] = identifiers;
+			return t.memberExpression(
+				createNestedMemberExpression(tail),
+				t.identifier(head)
+			);
+		}
+	}
+
+	return {
+		visitor: {
+			Program: {
+				exit(path) {
+					let dir = this.file.opts.filename.replace(/-/g, '_').split('/');
+					const jsLoc = dir.findIndex(x => x === 'js'),
+						file = dir[dir.length - 1],
+						exports = {};
+
+					// pass if [not in js folder] or [not ts file] or [is global.d.ts] or [is index.ts]
+					if (jsLoc === -1 || !file.endsWith('ts') || file === 'global.d.ts' || file === 'index.ts') return;
+
+					// simplify whole dir
+					dir = dir.slice(jsLoc + 1);
+					dir[dir.length - 1] = file.replace('.ts', '');
+
+					// sort order for follow-up
+					dir.unshift('window');
+					dir.push('_');
+					dir.reverse();
+
+					// visit all nodes
+					path.node.body.forEach((node, index) => {
+						if (t.isVariableDeclaration(node)) {
+							node.declarations.forEach((declaration) => {
+								if (t.isIdentifier(declaration.id)) {
+									exports[declaration.id.name] = declaration.id.name;
+								}
+							});
+						} else if (t.isFunctionDeclaration(node) && t.isIdentifier(node.id)) {
+							exports[node.id.name] = node.id.name;
+						}
+					});
+
+					// add check-exist if statements
+					for (let i = dir.length - 2; i > 0; i--) {
+						const nestedExpression = createNestedMemberExpression(dir.slice(i));
+						path.pushContainer('body',
+							t.ifStatement(
+								t.unaryExpression('!', nestedExpression),
+								t.expressionStatement(
+									t.assignmentExpression(
+										'=',
+										nestedExpression,
+										t.objectExpression([])
+									)
+								)
+							)
+						);
+					}
+
+					// export all global variables and functions
+					path.pushContainer('body',
+						// window.x.x.x._ = {...}
+						t.expressionStatement(
+							t.assignmentExpression(
+								'=',
+								createNestedMemberExpression(dir),
+								t.objectExpression(
+									Object.entries(exports).map(([k, v]) => {
+										return t.objectProperty(t.identifier(k), t.identifier(v));
+									})
+								)
+							)
+						)
+					);
+
+				}
+			}
+		}
+	};
+};
\ No newline at end of file
diff --git a/babel.config.js b/babel.config.js
index 1cb9413d5c9..1eae83290a8 100644
--- a/babel.config.js
+++ b/babel.config.js
@@ -17,6 +17,7 @@ module.exports = function (api) {
 	        ["@babel/plugin-proposal-decorators", { "legacy": true }],
             '@babel/plugin-proposal-class-properties',
             '@babel/plugin-proposal-object-rest-spread',
+	        './babel-plugin-expose-private-functions-and-variables',
         ],
 	    overrides: [{
 		    test: /[\\/]ext[\\/]//* treat as script for 3rd-party library */,
diff --git a/zkdoc/release-note b/zkdoc/release-note
index a7e3cf379e6..6edd1d8ac8a 100644
--- a/zkdoc/release-note
+++ b/zkdoc/release-note
@@ -20,6 +20,7 @@ ZK 10.0.0
   ZK-5533: Add all new HTML5 tags in ZK 10 ZHTML
   ZK-5049: Deprecate org.zkoss.zk.ui.uuidRecycle.disabled in ZK10
   ZK-5437: Upgrade WCAG with the lighthouse 10.x detection tools
+  ZK-4928: expose widget private functions and variables as public ones
 
 * Bugs
   ZK-5089: AfterSizeEvent doesn't return a correct size of a Window component