A series of 4 elements, which can be considered as 2 series of 2 elements

Below is a sentence from the manual about naming files that I'm working on.

Avoid including words that are clear from the parent path (2011), the file type (presentation), are obvious for some other reason, or not very important (my).

• Not recommended:

  my_presentations/
    2011/
      presentation_for_xyz_conference_2011.ppt
  

• Recommended:

  presentations/
    2011/
      xyz_conference.ppt
  

It seems to me that as "are obvious for some other reason" is not really a third item in "clear from..." sequence:

• there should be "or" between "parent path" and "the file type"
• there probably should be another "or before "are"

Avoid including words that are clear from the parent path or the file type, are obvious for some other reason or not very important.

Avoid including words that are clear from the parent path or the file type, or are obvious for some other reason or not very important.

Or maybe I'm simply overthink it?

Your example should be easier to read. Ordering them helps:

Avoid including words that are

(i) clear from the parent path (2011)

(ii) the file type (presentation),

(iii) obvious for some other reason, or

(iv) not very important (my)

The alternative is to rearrange to avoid ambiguous qualification by "clear from":

Avoid including words that are the file type (presentation); clear from the parent path (2011); obvious for some other reason, or not very important (my)