There are no major differences or issues detected between the two codes. It seems to be well-written JavaScript code for using markdown rendering engine with katex. No specific optimizations can be suggested without further context beyond what's provided here (e.g., about how these blocks will be used).

The use of export default {}; statement is appropriate because it makes the module global available at the beginning of the file, making things like import statements accessible earlier.

Since these changes were made before the most recent version of the Markdown.js library, the code still uses deprecated features from its pre-releases which might not work smoothly in a mature release; however, there seem to be no obvious errors or bugs based on our analysis.

Therefore, I do not see anything that needs adjustment. The code appears functional and clear according to current coding conventions.