What is "calibre:user_metadata:#formats" for?

[phossler]

In the OPF I noticed this meta:

<meta name="calibre:user_metadata:#formats" content="{&quot;is_custom&quot;: true, &quot;is_editable&quot;: true, &quot;link_column&quot;: &quot;value&quot;, &quot;rec_index&quot;: 22, &quot;label&quot;: &quot;formats&quot;, &quot;is_multiple&quot;: null, &quot;is_multiple2&quot;: {}, &quot;search_terms&quot;: [&quot;#formats&quot;], &quot;name&quot;: &quot;Books&quot;, &quot;category_sort&quot;: &quot;value&quot;, &quot;display&quot;: {&quot;contains_html&quot;: false, &quot;make_category&quot;: false, &quot;composite_template&quot;: &quot;{:'approximate_formats()'}&quot;, &quot;composite_sort&quot;: &quot;text&quot;, &quot;use_decorations&quot;: 0}, &quot;kind&quot;: &quot;field&quot;, &quot;#value#&quot;: &quot;AZW3,EPUB&quot;, &quot;is_category&quot;: false, &quot;column&quot;: &quot;value&quot;, &quot;is_csp&quot;: false, &quot;#extra#&quot;: null, &quot;datatype&quot;: &quot;composite&quot;, &quot;table&quot;: &quot;custom_column_2&quot;, &quot;colnum&quot;: 2}"/>

Even when I delete it, it seems to come back after I launch the editor from Calibre.

It doesn't seem to hurt anything, but it appears to relate to Calibre options, so I was wondering what it's for

[theducks]

You have a custom column by that name
Calibre will store it (polish,convert) so you don't lose it if you move the book elswhere

[phossler]

Thanks, but if I were to move it some where else, wouldn't that data be inaccessible?

Or is it just stored in the OPF but never used?

[theducks]

Originally Posted by phossler

Thanks, but if I were to move it some where else, wouldn't that data be inaccessible?

Or is it just stored in the OPF but never used?

Since many books (not touched by calibre update metadata) do not have the do not have this. it won't break calibre.

One has to wonder about the agony over a boilerplate header that only coders see.

[phossler]

Originally Posted by theducks

One has to wonder about the agony over a boilerplate header that only coders see.

I wasn't agonizing or it. I have to edit the OPF sometimes and I was curious is all since it doesn't seem to serve any purpose as far as the epub is concerned.

I can edit out and save it.

If I launch the editor directly, meta data is not there. If I launch the editor from Caliblre, Calibre adds the meta data for me. Even if I say to Quit without saving, Calibre updates the file with the additional meta data.

[eschwartz]

So tell calibre to stop.

Edit ==> Preferences ==> Integration with calibre (tab)
Uncheck "Update metadata embedded in the book when opening"

calibre embeds custom columns in the EPUB metadata during Send-to-device and Save-to-disk as well, it is meaningless to ask why it does so in the Editor specifically.
As theducks said -- it's stored so when you export the book, calibre can still retrieve the custom metadata if re-imported.

[phossler]

@eschwartz - thanks for the pointer to "Update metadata embedded in the book when opening".

That explains why I get a prompt from Editor to Save the file ... sometimes. If I had updated the book comments or something, and them went to edit it it'd prompt me to save even though I didn't think I made any changes. I always wondered about that.

That options stops all metadata being updated which I don't think I'd prefer, so I think my curiousity has been satisfied, and I won't agonize over it any more