I made some plasmid maps in a different software but the software makes some really thin lines for labels with no way of setting their thickness. Is there some way I can automatically select all these thin (0.088 mm) straight lines so I can adjust their thickness simultaneously?

Maybe it would be an option to do find and replace in a text editor but I'm not sure what to look for because 0.088mm and "0.088 mm" are not present. Can I use Microsoft Notepad with word wrap turned off? Thanks!

You should be able to do a find/replace in a text editor.

If you look for the style-element in xml editor, here is what it looks like for me (same thikness):
opacity:1;vector-effect:none;fill:none;fill-opacity:1;stroke:#000000;stroke-width:0.088;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-dashoffset:0;stroke-opacity:1

You also could try selecting one, then use Menu: Edit>select same >Stroke style.

That's awesome, thank you both for your responses! What a great feature that "select same" is.