Any object or layer that uses a number as a leading character in Illustrator will be converted into some crazy id in the resulting SVG.
For instance:
A layer called "1st-floor-rooms" in Illustrator will become "_x31_st-floor-rooms" in the SVG.

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An ugly phenomenon —
the text on top of an interactive box
blocks the mouseover effect.

To get around this,
we can use the following CSS
to make the cursor ignore all text elements:

text { pointer-events: none; }

http://www.petercollingridge.co.uk/data-visualisation/svg-mouseover-tricks

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Getting rid of rectangles <rect /> in SVG (they may unexpectedly disappear).
From primitive types to a path in Illustrator -
Object > Path > Simplify (Straight Lines).

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