New source found from dndbeyond.com

ddb_main/node_modules/@mui/material/Button/Button.js

@@ -10,7 +10,7 @@ import resolveProps from '@mui/utils/resolveProps';
 import composeClasses from '@mui/utils/composeClasses';
 import { alpha } from '@mui/system/colorManipulator';
 import styled, { rootShouldForwardProp } from '../styles/styled';
-import useThemeProps from '../styles/useThemeProps';
+import { useDefaultProps } from '../DefaultPropsProvider';
 import ButtonBase from '../ButtonBase';
 import capitalize from '../utils/capitalize';
 import buttonClasses, { getButtonUtilityClass } from './buttonClasses';
@@ -224,7 +224,7 @@ const Button = /*#__PURE__*/React.forwardRef(function Button(inProps, ref) {
   const contextProps = React.useContext(ButtonGroupContext);
   const buttonGroupButtonContextPositionClassName = React.useContext(ButtonGroupButtonContext);
   const resolvedProps = resolveProps(contextProps, inProps);
-  const props = useThemeProps({
+  const props = useDefaultProps({
     props: resolvedProps,
     name: 'MuiButton'
   });