Special symbols aren't always considered special; their significance depends on the context in which they are used. For example, in a JavaScript string, the plus sign (+) is not treated as a special character at all. However, it holds importance in contexts such as URLs, regular expressions, and mathematical formulas.
Regarding the \+
combination, it represents an unfamiliar escape sequence. Consequently, the backslash is simply disregarded:
When it comes to characters that are not explicitly defined [...], a preceding backslash is generally overlooked. It's worth noting that this practice is outdated and best avoided.