org-html-table-default-attributes

org-html-table-default-attributes is a variable defined in `ox-html.el'.
Its value is

(:border "2" :cellspacing "0" :cellpadding "6" :rules "groups" :frame "hsides")

Documentation:
Default attributes and values which will be used in table tags.
This is a plist where attributes are symbols, starting with
colons, and values are strings.

When exporting to HTML5, these values will be disregarded.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.