Working with Zotero on Landscapes, I found a bug in the TEI export routine, which had not been updated to take account of changes in the relationship between idno and biblStruct. I reported the bug and then created a patch for the TEI.js file on GitHub. In the process, I learned that if you directly edit a translation file in [home]/.zotero/zotero/XXX.default/zotero/translators, the effects are immediate even without restarting the app, so debugging is not difficult. There's more work to do on that TEI export (it uses note[@type='url'] where I think it should use a ref element or a ptr) but I'll wait and see if the current patch is accepted and works OK before proceeding.