Well, I’m glad to know its not that I’m missing something glaringly obvious but… the plot thickens…
I went out to a post and manually edited the description for it (note that right now it’s using a default of %seo_description% for each post). I entered a test description and then attempted the export again. Now, when I type “rank” to search for the available export fields, I do in fact see a new entry but it’s “rank_math_schema_BlogPosting.” I went ahead and exported all 140 posts of that field and sure enough, the post I edited is the only one that shows anything entered there. I thought this was good news, except this is what I see in that field on the export:
a:9:{s:8:”metadata”;a:4:{s:5:”title”;s:7:”Article”;s:4:”type”;s:8:”template”;s:9:”shortcode”;s:15:”s-(… it goes on forever)
Now I will note that in addition to changing the description for this test, I also changed a field in the same window for the schema type to change it from “article” to “blog post.” So, I went back and undid that change to see what happened. Sure enough, I no longer had the “rank_math_schema_BlogPosting” field after typing “rank” to see the available fields for export but rather “rank_math_schema_Article” and the same coded entry that goes on forever.
In doing this I realized maybe editing the description in that schema edit section isn’t correct (note I am simply following the directions Rank Math provides on how to edit your description) so I grabbed a plugin that adds an editor to each post where I can manually populate the “meta description” and tried that. After adding a description using that plugin I went back to WP All Export to check the fields. What was particularly interesting here was that the “rank_math_schema_Article” was still showing but not a meta description field. It also didn’t appear to change my description at all so let’s just assume that plugin didn’t do what it said it should.
I think the assumption that, because Rank Math has the description set to automatically populate using the first (however many) characters of the actual post, that it isn’t being seen as field like it should be because technically its not in use. What I can’t seem to figure out though is how to actually find and edit that field even manually, to get it to then appear in the export drop down.
After all of the above troubleshooting I realized that the page I found on how to edit the description (snippet) for each post on Rank Math’s site was misleading and that there was another way. I went back to one post and edited the snippet directly, rather than via their edit screen for the schema, and sure enough on my next visit to the Export I found “rank_math_description” as an option. I completed an export of it and tada it exported all 140 posts, with blanks in that field, save for the one where I entered “this is a test” where I see “this is a test” in the field.
So in short: The thinking that because a manual description hadn’t yet been entered for any post, the field wasn’t showing up in the export, was a correct one. Thank you!