Grabbed dndbeyond's source code

```
~/go/bin/sourcemapper -output ddb -jsurl https://media.dndbeyond.com/character-app/static/js/main.90aa78c5.js
```

ddb_main/tools/js/Shared/containers/panes/ProficiencyBonusPane/ProficiencyBonusPane.tsx

@@ -0,0 +1,51 @@
+import React from "react";
+import { connect } from "react-redux";
+
+import {
+  rulesEngineSelectors,
+  Constants,
+  RuleData,
+  RuleDataUtils,
+} from "@dndbeyond/character-rules-engine/es";
+
+import { HtmlContent } from "~/components/HtmlContent";
+import { Header } from "~/subApps/sheet/components/Sidebar/components/Header";
+
+import { SharedAppState } from "../../../stores/typings";
+
+interface Props {
+  ruleData: RuleData;
+}
+class ProficiencyBonusPane extends React.PureComponent<Props> {
+  render() {
+    const { ruleData } = this.props;
+
+    let rule = RuleDataUtils.getRule(
+      Constants.RuleKeyEnum.PROFICIENCY_BONUS,
+      ruleData
+    );
+    let description: string = "";
+    if (rule && rule.description) {
+      description = rule.description;
+    }
+
+    return (
+      <div className="ct-proficiency-bonus-pane">
+        <Header>Proficiency Bonus</Header>
+        <HtmlContent
+          className="ct-proficiency-bonus-pane__description"
+          html={description}
+          withoutTooltips
+        />
+      </div>
+    );
+  }
+}
+
+function mapStateToProps(state: SharedAppState) {
+  return {
+    ruleData: rulesEngineSelectors.getRuleData(state),
+  };
+}
+
+export default connect(mapStateToProps)(ProficiencyBonusPane);

ddb_main/tools/js/Shared/containers/panes/ProficiencyBonusPane/index.ts

@@ -0,0 +1,4 @@
+import ProficiencyBonusPane from "./ProficiencyBonusPane";
+
+export default ProficiencyBonusPane;
+export { ProficiencyBonusPane };