The TEI P4 `janus' elements are no longer sustainable:

a <corr resp="theobald" sic="table">babbl'd</corr>

<choice resp="theobald">
  <sic>table</sic>
  <corr>babbl'd</sic>
</choice>

The proposed <combine> element supports hierarchic grouping of editorial intervention:

it's a 
<combine>
 <add>bird</add>
 <del>plane</del>
</combine>