We could use:
https://github.com/mozilla/pdf.js/blob/c3d08580627471432a6ad0b2fdb948df64126afa/src/display/api.js#L929

and look at bit 4.

The following pdf:
https://orimi.com/pdf-test.pdf
is not editable in neither Acrobat nor Edge nor Foxit and nor Okular.
let scale = parseFloat(value);
    if (scale > 0) {
      this._setScaleUpdatePages(scale, value, noScroll,  false);
    } else {
      const currentPage = this._pages[this._currentPageNumber - 1];
      if (!currentPage) {
        return;
      }
      let hPadding = SCROLLBAR_PADDING,
        vPadding = VERTICAL_PADDING;
      if (this.isInPresentationMode) {
        hPadding = vPadding = 4;
      } else if (this.removePageBorders) {
        hPadding = vPadding = 0;
      } else if (this._scrollMode === ScrollMode.HORIZONTAL) {
        [hPadding, vPadding] = [vPadding, hPadding]; 
      }
      const pageWidthScale =
        (((this.container.clientWidth - hPadding) / currentPage.width) *
          currentPage.scale) /
        this._pageWidthScaleFactor;
      const pageHeightScale =
        ((this.container.clientHeight - vPadding) / currentPage.height) *
        currentPage.scale;
      switch (value) {
        case "page-actual":