Aligned to guideline, path optimized and some fixes to Blogger, Bluetooth, CloudFlare, CodePen, Delicious, Digidentity and Digital Ocean.

All were aligned accordingly and optimized to the following percentages:

Blogger - 23% and corrected color.
Bluetooth - 1% and corrected color.
CloudFlare - 12%
CodePen - 42% and corrected color contrast.
Delicious + 35% because I added a clipping path, for consistency.
Review it.
Digidentity - 0%
Digital Ocean + 20% No idea how to make it the same file size after
following the guideline.

Updated README with the new file sizes.

images/svg/codepen.svg

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+<svg stroke-linejoin="round" viewBox="0 0 512 512" xmlns="http://www.w3.org/2000/svg" aria-label="CodePen" role="img"><rect fill="#111" height="512" rx="15%" width="512"/><g fill="none" stroke="#e6e6e6" stroke-width="33"><path d="M81 198v116l175 117 175-117V198L256 81z"/><path d="M81 198l175 116 175-116M256 81v117"/><path d="M81 314l175-116 175 116M256 431V314"/></g></svg>