I have a modern jazz lead sheet “Just like that” from Peter Herbolzheimer in which the chords have rather unfamiliar notation. E♭9+11- is one, or Dm7♮. What do these mean?
Just guessing doesn't make much sense here. In such a case it's usually wise to actually listen, it's music after all! And listening reveals that the chord is actually an Eb7(#9,b5). You can hear the transition from the #5 in the previous chord to the b5 pretty clearly. So the previous chord actually also has a #5 (or b13):
So what probably happened is that they couldn't decide whether they should use a #11 or a b5 in the chord symbol, and they ended up with a bad compromise, namely b11, which doesn't make any sense.
And, as correctly pointed out in other answers, the D minor chord with the natural placed after the '7' is a slightly unusual way to denote a D minor major seventh chord (D-F-A-C#).
It seems a slightly unusual way to write out chord symbols in my experience.
However, guesswork says that Dm7♮ will be 'D minor, major seventh'. Made up from - D F A C♯. Sometimes written as DmM7.
The E♭9+11- should be 'E flat sharp nine flat eleven', containing E♭ G, B♭ D♭ F♯, A♭♭. Which doesn't make a lot of sense - that A♭♭ sounds the same as the M3 - G - so is meaningless as an extension to the basic chord - it might be technically 'correct', but I see no practical point in adding it.