code: function writeTableHead(browserPlatformType) {
    let browserNameKeys = Object.keys(browsers[browserPlatformType]);
    let output = '';
    if (browserPlatformType === 'webextensions') {
      output = '<table class="webext-summary-compat-table"><thead><tr><th style="width: 40%"></th>'
      let browserColumnWidth = 60/browserNameKeys.length;
      for (let browserNameKey of browserNameKeys) {
        output += `<th style="width:${browserColumnWidth}%">${browsers[browserPlatformType][browserNameKey]}</th>`;
      }
      output += "<tr></thead>";
    } else {
      output = `<div id="compat-${browserPlatformType}"><table class="compat-table"><thead><tr>`;
      output +=  '<th>Feature</th>';
      for (let browserNameKey of browserNameKeys) {
        output += `<th>${browsers[browserPlatformType][browserNameKey]}</th>`;
      }
      output += '</tr></thead>';
    }
    return output;
  }
docs: /*
  Write the table header.
  
  `browserPlatformType` is either "mobile", "desktop" or "webextensions"