Export names
Because of Blender's naming system, certain measures have been taken to preserve the original name of meshes and textures.
All the characters after the last . (period) are removed. Add an additional period if you want to preserve that.
Cube.001 will become Cube by this method.
The method is used for Object names, collection names (in mass export) and material texture names (also see below for that).
If you want to, for example export Cube.001 as Cube.001, you will have to append an additional period at the end of the name.
Cube.001.
An additional system is used for preserving the original textures name. In the shader editor, the label of the Image Texture node is set to the original name. This label is used for exporting the final texture name.
In the example above, the label is vehiclegrunge256. This will be used as the texture name. You can change the label from the Properties Menu (invoked by pressing N in the Shader Editor)
For convenience, there are certain exceptions to the above method. Suppose you change the image to a different image file, say test.png while the original texture name was vehiclegrunge256, it would be inconvenient to manually go to the Shader Editor to change the label. Furthermore, it is possible that the you forget to change the label altogether.
To address this issue, the label name is not used if it is not a substring of the image name.
So, if you have test.png selected as the image, and the original texture name was vehiclegrunge256, test will be used as the texture name as test is not a part of `vehiclegrunge256.
You will have to change the label in case the new image name is vehicle, and the original texture name was vehiclegrunge256 as now, vehicle is a part of the label.