Association between an FBX file and its folder containing materials

When a 3D model with applied textures is exported as a .fbx file, there is one resulting file and also a folder containing some (but not all) the used materials.

Am I correct in assuming that (1) the materials that are not placed in the corresponding folder are embedded in the .fbx file and (2) there is a link between the .fbx file and the folder, so that when (for example) you convert the .fbx file to a different format, everything associated with it (which is in that folder) will be taken into consideration?

The background reason for this question is this tutorial. In one of the paragraphs toward the end, it is advised to open the Autodesk FBX Converter and drag’n’drop your .fbx file in the left side, which implies drag’n’drop only that file (but remember you have a folder with some images, etc… that were put in there automatically as a result of the export process). Then, it essentially says if you check the size of the converted file, it’s bigger because it has embedded all the textures within this new .fbx file, which does not happen in my case…