Bookmarks—ArcGIS Pro | Documentation
you can import them
In the window that appears, browse to and select the bookmark file to import.
You can also import bookmark files (.dat file extension) from ArcGIS Desktop.
and you can export them to .bkmx
Manage bookmarks—ArcGIS Pro | Documentation
So apparently not.... but why not compare the format of *.dat and *.bkmx
This is a *.bkmx.... I don't have ArcMap. I did a big SNIP in the middle
{
"type" : "CIMBookmarkDocument",
"version" : "2.6.0",
"build" : 24776,
"spatialReference" : {
"wkid" : 2146,
"latestWkid" : 2951
},
"bookmarks" : [
{
"type" : "CIMBookmark",
"name" : "test",
"thumbnailImagePath" : "Qk02bAAAAAA
... HUGE SNIP ...
////////////////Pz8",
"camera" : {
"type" : "CIMViewCamera",
"pitch" : -90,
"scale" : 289.19531752143416,
"x" : 300018.13851199951,
"y" : 5000017.5265992843,
"z" : 97.054644200095083,
"viewportHeight" : 64.273787866714486,
"viewportWidth" : 77.97022599545484
},
"location" : {
"xmin" : 299979.153399001807,
"ymin" : 4999985.38970535062,
"xmax" : 300057.123624997213,
"ymax" : 5000049.6634932179,
"spatialReference" : {
"wkid" : 2146,
"latestWkid" : 2951
}
},
"timeRelation" : "esriTimeRelationOverlaps",
"description" : "<DIV STYLE=\"text-align:Left;font-size:12pt\"><P><SPAN>test bookmark</SPAN></P></DIV>"
}
]
}
... sort of retired...